Remove hardcoding of world limits (#1199)

* Remove hardcoding of world limits
 - seems to be working fine without the datapack for world height changing
 - particular attention should be given to LocalBlockVectorSet and MathMan changes

* update adapters

* Override getMinY in various classes and ensure selections have a world attached to them

* no message

* Address comments
 - Fix for lighting mode 1

* A few more changes

* Fix LocalBlockVectorSet

* Fix range statement

* Various fixes/comment-addressing
- There's not much point in having a different file name now for history. We've broken it before...
- Fix history read/write
- Fix range on for loops in CharBlocks

* undo bad CharBlocks change

* Fix history y level

* Fix biome history

* Fix lighting

* Fix /up

* Make regen fail not because of these changes

* Fixes for y < 0

* Fix isEmpty where only the uppermost chunksection is edited

* Fix javadocs/FAWE annotations

* Better explain why BiomeMath is removed

* If history task throws an error, it should only be caught and printed if not completing now.

* Min|max world heights for new patterns

* Load biomes from NMS instead of bukkit (#1200)

* Update adapters

* Update adapters

* Don't initialise BlockTypes when biomes aren't set up yet so all BiomeTypes.BIOME are no longer null thanks.

* Address some comments.

* rename layer -> sectionIndex to imply inclusivity

* Javadoctored.

Co-authored-by: NotMyFault <mc.cache@web.de>
Co-authored-by: Hannes Greule <SirYwell@users.noreply.github.com>

worldedit-bukkit/src/main/java/com/fastasyncworldedit/bukkit/adapter/Regenerator.java

@@ -266,8 +266,8 @@ public abstract class Regenerator<IChunkAccess, ProtoChunk extends IChunkAccess,
             });
         }
 
-        source = new SingleThreadQueueExtent();
+        source = new SingleThreadQueueExtent(originalBukkitWorld.getMinHeight(), originalBukkitWorld.getMaxHeight());
-        source.init(null, initSourceQueueCache(), null);
+        source.init(target, initSourceQueueCache(), null);
         return true;
     }
 

worldedit-bukkit/src/main/java/com/fastasyncworldedit/bukkit/util/MinecraftVersion.java

@@ -11,6 +11,7 @@ import javax.annotation.Nonnull;
 public class MinecraftVersion implements Comparable<MinecraftVersion> {
 
     public static final MinecraftVersion NETHER = new MinecraftVersion(1, 16);
+    public static final MinecraftVersion CAVES_17 = new MinecraftVersion(1, 17);
 
     private final int major;
     private final int minor;

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/WorldEditPlugin.java

@@ -49,6 +49,7 @@ import com.sk89q.worldedit.util.lifecycle.Lifecycled;
 import com.sk89q.worldedit.util.lifecycle.SimpleLifecycled;
 import com.sk89q.worldedit.world.World;
 import com.sk89q.worldedit.world.biome.BiomeType;
+import com.sk89q.worldedit.world.biome.BiomeTypes;
 import com.sk89q.worldedit.world.block.BlockCategory;
 import com.sk89q.worldedit.world.entity.EntityType;
 import com.sk89q.worldedit.world.gamemode.GameModes;
@@ -59,6 +60,7 @@ import org.apache.logging.log4j.Logger;
 import org.bstats.bukkit.Metrics;
 import org.bukkit.Bukkit;
 import org.bukkit.Material;
+import org.bukkit.NamespacedKey;
 import org.bukkit.Tag;
 import org.bukkit.block.Biome;
 import org.bukkit.command.BlockCommandSender;
@@ -234,17 +236,18 @@ public class WorldEditPlugin extends JavaPlugin {
         // datapacks aren't loaded until just before the world is, and bukkit has no event for this
         // so the earliest we can do this is in WorldInit
         setupTags();
+        setupBiomes(); // FAWE - load biomes later
         WorldEdit.getInstance().getEventBus().post(new PlatformReadyEvent(platform));
     }
 
     @SuppressWarnings({"deprecation", "unchecked"})
     private void initializeRegistries() {
-        // Biome
+        /* // FAWE start - move Biomes to their own method
         for (Biome biome : Biome.values()) {
             String lowerCaseBiomeName = biome.name().toLowerCase(Locale.ROOT);
             BiomeType.REGISTRY.register("minecraft:" + lowerCaseBiomeName, new BiomeType("minecraft:" + lowerCaseBiomeName));
         }
-        /*
+        // FAWE end
 
         // Block & Item
         for (Material material : Material.values()) {
@@ -304,6 +307,30 @@ public class WorldEditPlugin extends JavaPlugin {
                     "The version of Spigot/Paper you are using doesn't support Tags. The usage of tags with WorldEdit will not work until you update.");
         }
     }
+ 
+    // FAWE start
+    private void setupBiomes() {
+        if (this.adapter.value().isPresent()) {
+            // We don't know which world is the one with the data packs
+            // so we just loop over them. Doesn't hurt
+            for (org.bukkit.World world : Bukkit.getWorlds()) {
+                // cast is needed, thanks to raw types <3
+                for (final NamespacedKey biome : ((BukkitImplAdapter<?>) adapter.value().get()).getRegisteredBiomes(world)) {
+                    if (BiomeType.REGISTRY.get(biome.toString()) == null) { // only register once
+                        BiomeType.REGISTRY.register(biome.toString(), new BiomeType(biome.toString()));
+                    }
+                }
+            }
+        } else {
+            LOGGER.warn("Failed to load biomes via adapter (not present). Will load via bukkit");
+            for (Biome biome : Biome.values()) {
+                if (BiomeType.REGISTRY.get(biome.toString()) == null) { // only register once
+                    BiomeType.REGISTRY.register(biome.getKey().toString(), new BiomeType(biome.getKey().toString()));
+                }
+            }
+        }
+    }
+    // FAWE end
 
     private void loadAdapter() {
         WorldEdit worldEdit = WorldEdit.getInstance();

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/adapter/BukkitImplAdapter.java

@@ -50,7 +50,9 @@ import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockType;
 import com.sk89q.worldedit.world.item.ItemType;
 import com.sk89q.worldedit.world.registry.BlockMaterial;
+import org.bukkit.Keyed;
 import org.bukkit.Location;
+import org.bukkit.NamespacedKey;
 import org.bukkit.World;
 import org.bukkit.WorldCreator;
 import org.bukkit.block.Biome;
@@ -60,9 +62,11 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
 import javax.annotation.Nullable;
+import java.util.Arrays;
 import java.util.Map;
 import java.util.OptionalInt;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 /**
  * An interface for adapters of various Bukkit implementations.
@@ -304,6 +308,18 @@ public interface BukkitImplAdapter<T> extends IBukkitAdapter {
         return Biome.BADLANDS.ordinal();
     }
 
+    /**
+     * Returns an iterable of all biomes known to the server.
+     *
+     * @param world the world to load the registered biomes from.
+     * @return all biomes known to the server.
+     */
+    default Iterable<NamespacedKey> getRegisteredBiomes(World world) {
+        return Arrays.stream(Biome.values())
+                .map(Keyed::getKey)
+                .collect(Collectors.toList());
+    }
+
     default RelighterFactory getRelighterFactory() {
         return new NMSRelighterFactory(); // TODO implement in adapters instead
     }

worldedit-core/src/main/java/com/fastasyncworldedit/core/FaweAPI.java

@@ -270,17 +270,22 @@ public class FaweAPI {
         RegionWrapper bounds = new RegionWrapper(
                 origin.getBlockX() - radius,
                 origin.getBlockX() + radius,
+                extent.getMinY(),
+                extent.getMaxY(),
                 origin.getBlockZ() - radius,
                 origin.getBlockZ() + radius
         );
-        RegionWrapper boundsPlus = new RegionWrapper(bounds.minX - 64, bounds.maxX + 512, bounds.minZ - 64, bounds.maxZ + 512);
+        RegionWrapper boundsPlus = new RegionWrapper(bounds.minX - 64, bounds.maxX + 512, bounds.minY, bounds.maxY,
+                bounds.minZ - 64,
+                bounds.maxZ + 512);
         HashSet<RegionWrapper> regionSet = Sets.<RegionWrapper>newHashSet(bounds);
         ArrayList<DiskStorageHistory> result = new ArrayList<>();
         for (File file : files) {
             UUID uuid = UUID.fromString(file.getParentFile().getName());
             DiskStorageHistory dsh = new DiskStorageHistory(world, uuid, Integer.parseInt(file.getName().split("\\.")[0]));
             SimpleChangeSetSummary summary = dsh.summarize(boundsPlus, shallow);
-            RegionWrapper region = new RegionWrapper(summary.minX, summary.maxX, summary.minZ, summary.maxZ);
+            RegionWrapper region = new RegionWrapper(summary.minX, summary.maxX, extent.getMinY(), extent.getMaxY(), summary.minZ,
+                    summary.maxZ);
             boolean encompassed = false;
             boolean isIn = false;
             for (RegionWrapper allowed : regionSet) {

worldedit-core/src/main/java/com/fastasyncworldedit/core/FaweCache.java

@@ -64,9 +64,6 @@ public enum FaweCache implements Trimable {
     private static final Logger LOGGER = LogManagerCompat.getLogger();
 
     public final int BLOCKS_PER_LAYER = 4096;
-    public final int CHUNK_LAYERS = 16;
-    public final int WORLD_HEIGHT = CHUNK_LAYERS << 4;
-    public final int WORLD_MAX_Y = WORLD_HEIGHT - 1;
 
     public final char[] EMPTY_CHAR_4096 = new char[4096];
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/BlendBall.java

@@ -24,7 +24,8 @@ public class BlendBall implements Brush {
 
         int[] frequency = new int[BlockTypes.size()];
 
-        int maxY = editSession.getMaximumPoint().getBlockY();
+        int maxY = editSession.getMaxY();
+        int minY = editSession.getMinY();
 
         for (int x = -outsetSize; x <= outsetSize; x++) {
             int x0 = x + tx;
@@ -43,7 +44,7 @@ public class BlendBall implements Brush {
                     for (int ox = -1; ox <= 1; ox++) {
                         for (int oz = -1; oz <= 1; oz++) {
                             for (int oy = -1; oy <= 1; oy++) {
-                                if (oy + y0 < 0 || oy + y0 > maxY) {
+                                if (oy + y0 < minY || oy + y0 > maxY) {
                                     continue;
                                 }
                                 BlockState state = editSession.getBlock(x0 + ox, y0 + oy, z0 + oz);

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/CommandBrush.java

@@ -41,7 +41,8 @@ public class CommandBrush implements Brush {
                 .replace("{size}", Integer.toString(radius));
 
         Player player = editSession.getPlayer();
-        Location face = player.getBlockTraceFace(256, true);
+        //Use max world height to allow full coverage of the world height
+        Location face = player.getBlockTraceFace(editSession.getWorld().getMaxY(), true);
         if (face == null) {
             position = position.add(0, 1, 1);
         } else {

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/CopyPastaBrush.java

@@ -78,7 +78,8 @@ public class CopyPastaBrush implements Brush, ResettableTool {
             };
             // Add origin
             mask.test(position);
-            RecursiveVisitor visitor = new RecursiveVisitor(mask, new NullRegionFunction(), (int) size);
+            RecursiveVisitor visitor = new RecursiveVisitor(mask, new NullRegionFunction(), (int) size, editSession.getMinY(),
+                    editSession.getMaxY());
             visitor.visit(position);
             Operations.completeBlindly(visitor);
             // Build the clipboard

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/FallingSphere.java

@@ -16,6 +16,7 @@ public class FallingSphere implements Brush {
         int py = position.getBlockY();
         int pz = position.getBlockZ();
         int maxY = editSession.getMaxY();
+        int minY = editSession.getMinY();
 
         int radius = (int) Math.round(size);
         int radiusSqr = (int) Math.round(size * size);
@@ -37,10 +38,10 @@ public class FallingSphere implements Brush {
                 }
 
                 int yRadius = MathMan.usqrt(remainingY);
-                int startY = Math.max(0, py - yRadius);
+                int startY = Math.max(minY, py - yRadius);
                 int endY = Math.min(maxY, py + yRadius);
 
-                int heightY = editSession.getHighestTerrainBlock(ax, az, 0, endY);
+                int heightY = editSession.getHighestTerrainBlock(ax, az, startY, endY);
                 if (heightY < startY) {
                     int diff = startY - heightY;
                     startY -= diff;

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/FlattenBrush.java

@@ -21,9 +21,11 @@ public class FlattenBrush extends HeightBrush {
             boolean layers,
             boolean smooth,
             Clipboard clipboard,
-            ScalableHeightMap.Shape shape
+            ScalableHeightMap.Shape shape,
+            int minY,
+            int maxY
     ) {
-        super(stream, rotation, yscale, layers, smooth, clipboard, shape);
+        super(stream, rotation, yscale, layers, smooth, clipboard, shape, minY, maxY);
     }
 
     @Override

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/HeightBrush.java

@@ -27,8 +27,9 @@ public class HeightBrush implements Brush {
     public final boolean layers;
     public final boolean smooth;
 
-    public HeightBrush(InputStream stream, int rotation, double yscale, boolean layers, boolean smooth, Clipboard clipboard) {
+    public HeightBrush(InputStream stream, int rotation, double yscale, boolean layers, boolean smooth, Clipboard clipboard,
-        this(stream, rotation, yscale, layers, smooth, clipboard, ScalableHeightMap.Shape.CONE);
+                       int minY, int maxY) {
+        this(stream, rotation, yscale, layers, smooth, clipboard, ScalableHeightMap.Shape.CONE, minY, maxY);
     }
 
     public HeightBrush(
@@ -38,7 +39,9 @@ public class HeightBrush implements Brush {
             boolean layers,
             boolean smooth,
             Clipboard clipboard,
-            ScalableHeightMap.Shape shape
+            ScalableHeightMap.Shape shape,
+            int minY,
+            int maxY
     ) {
         this.rotation = (rotation / 90) % 4;
         this.yscale = yscale;
@@ -46,14 +49,14 @@ public class HeightBrush implements Brush {
         this.smooth = smooth;
         if (stream != null) {
             try {
-                heightMap = ScalableHeightMap.fromPNG(stream);
+                heightMap = ScalableHeightMap.fromPNG(stream, minY, maxY);
             } catch (IOException e) {
                 throw new FaweException(Caption.of("fawe.worldedit.brush.brush.height.invalid"));
             }
         } else if (clipboard != null) {
-            heightMap = ScalableHeightMap.fromClipboard(clipboard);
+            heightMap = ScalableHeightMap.fromClipboard(clipboard, minY, maxY);
         } else {
-            heightMap = ScalableHeightMap.fromShape(shape);
+            heightMap = ScalableHeightMap.fromShape(shape, minY, maxY);
         }
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/ImageBrush.java

@@ -102,7 +102,7 @@ public class ImageBrush implements Brush {
                         colorFunction,
                         editSession,
                         session.getTextureUtil()
-                ), vector -> true, Integer.MAX_VALUE);
+                ), vector -> true, Integer.MAX_VALUE, editSession.getMinY(), editSession.getMaxY());
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));
         visitor.visit(center);
         Operations.completeBlindly(visitor);

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/LayerBrush.java

@@ -36,10 +36,12 @@ public class LayerBrush implements Brush {
                 BlockTypes.AIR,
                 BlockTypes.CAVE_AIR,
                 BlockTypes.VOID_AIR
-        ));
+        ), editSession.getMinY(), editSession.getMaxY());
         final SolidBlockMask solid = new SolidBlockMask(editSession);
         final RadiusMask radius = new RadiusMask(0, (int) size);
-        visitor = new RecursiveVisitor(new MaskIntersection(adjacent, solid, radius), function -> true);
+        visitor = new RecursiveVisitor(new MaskIntersection(adjacent, solid, radius), funcion -> true, Integer.MAX_VALUE,
+                editSession.getMinY(),
+                editSession.getMaxY());
         visitor.visit(position);
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));
         Operations.completeBlindly(visitor);
@@ -48,7 +50,7 @@ public class LayerBrush implements Brush {
             int depth = visitor.getDepth();
             Pattern currentPattern = layers[depth];
             return currentPattern.apply(editSession, pos, pos);
-        }, layers.length - 1);
+        }, layers.length - 1, editSession.getMinY(), editSession.getMaxY());
         for (BlockVector3 pos : visited) {
             visitor.visit(pos);
         }

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/RecurseBrush.java

@@ -48,7 +48,7 @@ public class RecurseBrush implements Brush {
             visitor.visit(position);
             Operations.completeBlindly(visitor);
         } else {
-            RecursiveVisitor visitor = new RecursiveVisitor(mask, replace, radius) {
+            RecursiveVisitor visitor = new RecursiveVisitor(mask, replace, radius, editSession.getMinY(), editSession.getMaxY()) {
                 @Override
                 public boolean isVisitable(BlockVector3 from, BlockVector3 to) {
                     int y = to.getBlockY();

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/ScatterBrush.java

@@ -52,7 +52,8 @@ public class ScatterBrush implements Brush {
 
         final int distance = Math.min((int) size, this.distance);
 
-        RecursiveVisitor visitor = new RecursiveVisitor(new MaskIntersection(radius, surface), function -> true);
+        RecursiveVisitor visitor = new RecursiveVisitor(new MaskIntersection(radius, surface), function -> true,
+                Integer.MAX_VALUE, editSession.getMinY(), editSession.getMaxY());
         visitor.visit(position);
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));
         Operations.completeBlindly(visitor);

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/SplatterBrush.java

@@ -42,7 +42,7 @@ public class SplatterBrush extends ScatterBrush {
         SurfaceMask surface = new SurfaceMask(editSession);
 
         RecursiveVisitor visitor = new RecursiveVisitor(new SplatterBrushMask(editSession, position, size2, surface, placed),
-                vector -> editSession.setBlock(vector, finalPattern), recursion
+                vector -> editSession.setBlock(vector, finalPattern), recursion, editSession.getMinY(), editSession.getMaxY()
         );
         visitor.setMaxBranch(2);
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/StencilBrush.java

@@ -21,8 +21,9 @@ public class StencilBrush extends HeightBrush {
 
     private final boolean onlyWhite;
 
-    public StencilBrush(InputStream stream, int rotation, double yscale, boolean onlyWhite, Clipboard clipboard) {
+    public StencilBrush(InputStream stream, int rotation, double yscale, boolean onlyWhite, Clipboard clipboard, int minY,
-        super(stream, rotation, yscale, false, true, clipboard);
+                        int maxY) {
+        super(stream, rotation, yscale, false, true, clipboard, minY, maxY);
         this.onlyWhite = onlyWhite;
     }
 
@@ -32,15 +33,16 @@ public class StencilBrush extends HeightBrush {
         int size = (int) sizeDouble;
         int size2 = (int) (sizeDouble * sizeDouble);
         int maxY = editSession.getMaxY();
+        int minY = editSession.getMinY();
         int add;
         if (yscale < 0) {
-            add = maxY;
+            add = maxY - minY;
         } else {
             add = 0;
         }
         final HeightMap map = getHeightMap();
         map.setSize(size);
-        int cutoff = onlyWhite ? maxY : 0;
+        int cutoff = onlyWhite ? maxY - minY : 0;
         final SolidBlockMask solid = new SolidBlockMask(editSession);
 
         Location loc = editSession.getPlayer().getLocation();
@@ -48,7 +50,7 @@ public class StencilBrush extends HeightBrush {
         float pitch = loc.getPitch();
         AffineTransform transform = new AffineTransform().rotateY((-yaw) % 360).rotateX(pitch - 90).inverse();
 
-        double scale = (yscale / sizeDouble) * (maxY + 1);
+        double scale = (yscale / sizeDouble) * (maxY - minY + 1);
         RecursiveVisitor visitor =
                 new RecursiveVisitor(new StencilBrushMask(
                         editSession,
@@ -63,7 +65,7 @@ public class StencilBrush extends HeightBrush {
                         maxY,
                         pattern
                 ),
-                        vector -> true, Integer.MAX_VALUE
+                        vector -> true, Integer.MAX_VALUE, editSession.getMinY(), editSession.getMaxY()
                 );
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));
         visitor.visit(center);

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/SurfaceSphereBrush.java

@@ -25,7 +25,7 @@ public class SurfaceSphereBrush implements Brush {
         final RadiusMask radius = new RadiusMask(0, (int) size);
         RecursiveVisitor visitor = new RecursiveVisitor(
                 new MaskIntersection(surface, radius),
-                vector -> editSession.setBlock(vector, pattern)
+                vector -> editSession.setBlock(vector, pattern), Integer.MAX_VALUE, editSession.getMinY(), editSession.getMaxY()
         );
         visitor.visit(position);
         visitor.setDirections(Arrays.asList(BreadthFirstSearch.DIAGONAL_DIRECTIONS));

worldedit-core/src/main/java/com/fastasyncworldedit/core/command/tool/brush/SurfaceSpline.java

@@ -37,13 +37,14 @@ public class SurfaceSpline implements Brush {
     public void build(EditSession editSession, BlockVector3 pos, Pattern pattern, double radius) throws
             MaxChangedBlocksException {
         int maxY = editSession.getMaxY();
+        int minY = editSession.getMinY();
         if (path.isEmpty() || !pos.equals(path.get(path.size() - 1))) {
             int max = editSession.getNearestSurfaceTerrainBlock(
                     pos.getBlockX(),
                     pos.getBlockZ(),
                     pos.getBlockY(),
-                    0,
+                    minY,
-                    editSession.getMaxY()
+                    maxY
             );
             if (max == -1) {
                 return;
@@ -71,7 +72,7 @@ public class SurfaceSpline implements Brush {
             final int tipx = MathMan.roundInt(tipv.getX());
             final int tipz = (int) tipv.getZ();
             int tipy = MathMan.roundInt(tipv.getY());
-            tipy = editSession.getNearestSurfaceTerrainBlock(tipx, tipz, tipy, 0, maxY);
+            tipy = editSession.getNearestSurfaceTerrainBlock(tipx, tipz, tipy, minY, maxY);
             if (tipy == -1) {
                 continue;
             }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/mask/AdjacentMaskParser.java

@@ -5,9 +5,13 @@ import com.fastasyncworldedit.core.function.mask.AdjacentAnyMask;
 import com.fastasyncworldedit.core.function.mask.AdjacentMask;
 import com.sk89q.worldedit.WorldEdit;
 import com.sk89q.worldedit.command.util.SuggestionHelper;
+import com.sk89q.worldedit.entity.Player;
 import com.sk89q.worldedit.extension.input.InputParseException;
 import com.sk89q.worldedit.extension.input.ParserContext;
+import com.sk89q.worldedit.extension.platform.Locatable;
+import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.function.mask.Mask;
+import com.sk89q.worldedit.world.World;
 
 import javax.annotation.Nonnull;
 import java.util.stream.Stream;
@@ -43,7 +47,7 @@ public class AdjacentMaskParser extends RichParser<Mask> {
             max = min;
         }
         if (max >= 8 && min == 1) {
-            return new AdjacentAnyMask(subMask);
+            return new AdjacentAnyMask(subMask, context.getMinY(), context.getMaxY());
         }
         return new AdjacentMask(subMask, min, max);
     }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/mask/RichOffsetMaskParser.java

@@ -43,7 +43,7 @@ public class RichOffsetMaskParser extends RichParser<Mask> {
         int y = Integer.parseInt(arguments[1]);
         int z = Integer.parseInt(arguments[2]);
         Mask submask = worldEdit.getMaskFactory().parseFromInput(arguments[3], context);
-        return new OffsetMask(submask, BlockVector3.at(x, y, z));
+        return new OffsetMask(submask, BlockVector3.at(x, y, z), context.getMinY(), context.getMaxY());
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/pattern/OffsetPatternParser.java

@@ -58,10 +58,7 @@ public class OffsetPatternParser extends RichParser<Pattern> {
         } else {
             x = y = z = Integer.parseInt(arguments[1]);
         }
-        Extent extent = context.requireExtent();
+        return new OffsetPattern(inner, x, y, z, context.getMinY(), context.getMaxY());
-        int minY = extent.getMinY();
-        int maxY = extent.getMaxY();
-        return new OffsetPattern(inner, x, y, z, minY, maxY);
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/pattern/RandomOffsetPatternParser.java

@@ -58,8 +58,7 @@ public class RandomOffsetPatternParser extends RichParser<Pattern> {
         } else {
             x = y = z = Integer.parseInt(arguments[1]);
         }
-        Extent extent = context.requireExtent();
+        return new RandomOffsetPattern(inner, x, y, z, context.getMinY(), context.getMaxY());
-        return new RandomOffsetPattern(inner, x, y, z, extent.getMinY(), extent.getMaxY());
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/pattern/RelativePatternParser.java

@@ -41,8 +41,7 @@ public class RelativePatternParser extends RichParser<Pattern> {
             ));
         }
         Pattern inner = this.worldEdit.getPatternFactory().parseFromInput(input[0], context);
-        Extent extent = context.requireExtent();
+        return new RelativePattern(inner, context.getMinY(), context.getMaxY());
-        return new RelativePattern(inner, extent.getMinY(), extent.getMaxY());
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/pattern/SolidRandomOffsetPatternParser.java

@@ -58,8 +58,7 @@ public class SolidRandomOffsetPatternParser extends RichParser<Pattern> {
         } else {
             x = y = z = Integer.parseInt(arguments[1]);
         }
-        Extent extent = context.requireExtent();
+        return new SolidRandomOffsetPattern(inner, x, y, z, context.getMinY(), context.getMaxY());
-        return new SolidRandomOffsetPattern(inner, x, y, z, extent.getMinY(), extent.getMaxY());
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extension/factory/parser/pattern/SurfaceRandomOffsetPatternParser.java

@@ -47,8 +47,7 @@ public class SurfaceRandomOffsetPatternParser extends RichParser<Pattern> {
         }
         Pattern inner = this.worldEdit.getPatternFactory().parseFromInput(arguments[0], context);
         int distance = Integer.parseInt(arguments[1]);
-        Extent extent = context.requireExtent();
+        return new SurfaceRandomOffsetPattern(inner, distance, context.getMinY(), context.getMaxY());
-        return new SurfaceRandomOffsetPattern(inner, distance, extent.getMinY(), extent.getMaxY());
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/ExtentHeightCacher.java

@@ -44,7 +44,7 @@ public class ExtentHeightCacher extends PassthroughExtent {
             index = rx + (rz << 8);
         }
         int result = cacheHeights[index] & 0xFF;
-        if (result == 0) {
+        if (result == minY) {
             cacheHeights[index] = (byte) (result = lastY = super
                     .getNearestSurfaceTerrainBlock(x, z, lastY, minY, maxY));
         }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/NullExtent.java

@@ -217,6 +217,11 @@ public class NullExtent extends FaweRegionExtent implements IBatchProcessor {
         throw reason;
     }
 
+    @Override
+    public int getMinY() {
+        throw reason;
+    }
+
     @Override
     public BlockArrayClipboard lazyCopy(Region region) {
         throw reason;
@@ -273,21 +278,6 @@ public class NullExtent extends FaweRegionExtent implements IBatchProcessor {
         throw reason;
     }
 
-    @Override
-    public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, boolean ignoreAir) {
-        throw reason;
-    }
-
-    @Override
-    public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY) {
-        throw reason;
-    }
-
-    @Override
-    public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax) {
-        throw reason;
-    }
-
     @Override
     public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax, Mask mask) {
         throw reason;

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/filter/block/ChunkFilterBlock.java

@@ -71,7 +71,7 @@ public abstract class ChunkFilterBlock extends AbstractExtentFilterBlock {
      */
     public final IChunkSet filter(IChunk chunk, IChunkGet get, IChunkSet set, Filter filter) {
         initChunk(chunk.getX(), chunk.getZ());
-        for (int layer = 0; layer < 16; layer++) {
+        for (int layer = get.getMinSectionIndex(); layer <= get.getMaxSectionIndex(); layer++) {
             if (set.hasSection(layer)) {
                 initLayer(get, set, layer);
                 filter(filter);
@@ -87,7 +87,7 @@ public abstract class ChunkFilterBlock extends AbstractExtentFilterBlock {
         if (region != null) {
             region.filter(chunk, filter, this, get, set, full);
         } else {
-            for (int layer = 0; layer < 16; layer++) {
+            for (int layer = get.getMinSectionIndex(); layer <= get.getMaxSectionIndex(); layer++) {
                 if ((!full && !get.hasSection(layer)) || !filter.appliesLayer(chunk, layer)) {
                     continue;
                 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/LimitExtent.java

@@ -119,92 +119,92 @@ public class LimitExtent extends AbstractDelegateExtent {
 
     @Override
     public int getHighestTerrainBlock(int x, int z, int minY, int maxY) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getHighestTerrainBlock(x, z, minY, maxY);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getHighestTerrainBlock(int x, int z, int minY, int maxY, Mask filter) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getHighestTerrainBlock(x, z, minY, maxY, filter);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getNearestSurfaceLayer(int x, int z, int y, int minY, int maxY) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceLayer(x, z, y, minY, maxY);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, boolean ignoreAir) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, ignoreAir);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, failedMin, failedMax);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
     @Override
     public int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax, Mask mask) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, failedMin, failedMax, mask);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 
@@ -219,14 +219,14 @@ public class LimitExtent extends AbstractDelegateExtent {
             int failedMax,
             boolean ignoreAir
     ) {
-        limit.THROW_MAX_CHECKS(FaweCache.IMP.WORLD_HEIGHT);
+        limit.THROW_MAX_CHECKS(maxY - minY + 1);
         try {
             return super.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, failedMin, failedMax, ignoreAir);
         } catch (FaweException e) {
             if (!limit.MAX_FAILS()) {
                 throw e;
             }
-            return 0;
+            return minY;
         }
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/heightmap/ArrayHeightMap.java

@@ -11,7 +11,15 @@ public class ArrayHeightMap extends ScalableHeightMap {
     private double rx;
     private double rz;
 
-    public ArrayHeightMap(byte[][] height) {
+    /**
+     * New height map represented by byte array[][] of values x*z to be scaled given a set size
+     *
+     * @param height array of height values
+     * @param minY min y value allowed to be set. Inclusive.
+     * @param maxY max y value allowed to be set. Inclusive.
+     */
+    public ArrayHeightMap(byte[][] height, int minY, int maxY) {
+        super(minY, maxY);
         setSize(5);
         this.height = height;
         this.width = height.length;

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/heightmap/FlatScalableHeightMap.java

@@ -2,8 +2,15 @@ package com.fastasyncworldedit.core.extent.processor.heightmap;
 
 public class FlatScalableHeightMap extends ScalableHeightMap {
 
-    public FlatScalableHeightMap() {
+    /**
-        super();
+     * New height map where the returned height is the minmum height value if outside the size, otherwise returns height equal
+     * to size.
+     *
+     * @param minY min y value allowed to be set. Inclusive.
+     * @param maxY max y value allowed to be set. Inclusive.
+     */
+    public FlatScalableHeightMap(int minY, int maxY) {
+        super(minY, maxY);
     }
 
     @Override
@@ -12,7 +19,7 @@ public class FlatScalableHeightMap extends ScalableHeightMap {
         int dz = Math.abs(z);
         int d2 = dx * dx + dz * dz;
         if (d2 > size2) {
-            return 0;
+            return minY;
         }
         return size;
     }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/heightmap/HeightMap.java

@@ -18,7 +18,6 @@ public interface HeightMap {
 
     void setSize(int size);
 
-
     default void perform(
             EditSession session,
             Mask mask,
@@ -83,8 +82,8 @@ public interface HeightMap {
             boolean towards,
             final boolean layers
     ) {
-        BlockVector3 top = session.getMaximumPoint();
+        int maxY = session.getMaxY();
-        int maxY = top.getBlockY();
+        int minY = session.getMinY();
         int diameter = 2 * size + 1;
         int centerX = pos.getBlockX();
         int centerZ = pos.getBlockZ();
@@ -121,15 +120,15 @@ public interface HeightMap {
                     }
                     int height;
                     if (layers) {
-                        height = tmpY = session.getNearestSurfaceLayer(xx, zz, tmpY, 0, maxY);
+                        height = tmpY = session.getNearestSurfaceLayer(xx, zz, tmpY, minY, maxY);
                     } else {
-                        height = tmpY = session.getNearestSurfaceTerrainBlock(xx, zz, tmpY, 0, maxY);
+                        height = tmpY = session.getNearestSurfaceTerrainBlock(xx, zz, tmpY, minY, maxY);
                         if (height == -1) {
                             continue;
                         }
                     }
                     oldData[index] = height;
-                    if (height == 0) {
+                    if (height == minY) {
                         newData[index] = centerY;
                         continue;
                     }
@@ -137,8 +136,9 @@ public interface HeightMap {
                     int diff = targetY - height;
                     double raiseScaled = diff * (raisePow * sizePowInv);
                     double raiseScaledAbs = Math.abs(raiseScaled);
-                    int random = ThreadLocalRandom.current().nextInt(256) < (int) ((Math.ceil(raiseScaledAbs) - Math.floor(
+                    int random =
-                            raiseScaledAbs)) * 256) ? (diff > 0 ? 1 : -1) : 0;
+                            ThreadLocalRandom.current().nextInt(maxY + 1 - minY) - minY < (int) ((Math.ceil(raiseScaledAbs) - Math.floor(
+                            raiseScaledAbs)) * (maxY + 1 - minY)) ? (diff > 0 ? 1 : -1) : 0;
                     int raiseScaledInt = (int) raiseScaled + random;
                     newData[index] = height + raiseScaledInt;
                 }
@@ -166,20 +166,22 @@ public interface HeightMap {
                             break;
                     }
                     if (layers) {
-                        height = session.getNearestSurfaceLayer(xx, zz, height, 0, maxY);
+                        height = session.getNearestSurfaceLayer(xx, zz, height, minY, maxY);
                     } else {
-                        height = session.getNearestSurfaceTerrainBlock(xx, zz, height, 0, maxY);
+                        height = session.getNearestSurfaceTerrainBlock(xx, zz, height, minY, maxY);
-                        if (height == -1) {
+                        if (height == minY - 1) {
                             continue;
                         }
                     }
                     oldData[index] = height;
-                    if (height == 0) {
+                    if (height == minY) {
                         newData[index] = centerY;
                         continue;
                     }
                     raise = (yscale * raise);
-                    int random = ThreadLocalRandom.current().nextInt(256) < (int) ((raise - (int) raise) * (256)) ? 1 : 0;
+                    int random =
+                            ThreadLocalRandom.current().nextInt(maxY + 1 - minY) - minY < (int) ((raise - (int) raise) * (maxY - minY + 1))
+                            ? 1 : 0;
                     int newHeight = height + (int) raise + random;
                     newData[index] = newHeight;
                 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/heightmap/ScalableHeightMap.java

@@ -18,20 +18,26 @@ public class ScalableHeightMap implements HeightMap {
 
     public int size2;
     public int size;
+    protected int minY;
+    protected int maxY;
 
     public enum Shape {
         CONE,
         CYLINDER,
     }
 
-    public ScalableHeightMap() {
+    /**
+     * New height map.
+     *
+     * @param minY min y value allowed to be set. Inclusive.
+     * @param maxY max y value allowed to be set. Inclusive.
+     */
+    public ScalableHeightMap(final int minY, final int maxY) {
+        this.minY = minY;
+        this.maxY = maxY;
         setSize(5);
     }
 
-    public ScalableHeightMap(int size) {
-        setSize(size);
-    }
-
     @Override
     public void setSize(int size) {
         this.size = size;
@@ -44,29 +50,29 @@ public class ScalableHeightMap implements HeightMap {
         int dz = Math.abs(z);
         int d2 = dx * dx + dz * dz;
         if (d2 > size2) {
-            return 0;
+            return minY;
         }
-        return Math.max(0, size - MathMan.sqrtApprox(d2));
+        return Math.max(minY, size - MathMan.sqrtApprox(d2));
     }
 
-    public static ScalableHeightMap fromShape(Shape shape) {
+    public static ScalableHeightMap fromShape(Shape shape, int minY, int maxY) {
         switch (shape) {
             default:
             case CONE:
-                return new ScalableHeightMap();
+                return new ScalableHeightMap(minY, maxY);
             case CYLINDER:
-                return new FlatScalableHeightMap();
+                return new FlatScalableHeightMap(minY, maxY);
         }
     }
 
-    public static ScalableHeightMap fromClipboard(Clipboard clipboard) {
+    public static ScalableHeightMap fromClipboard(Clipboard clipboard, int minY, int maxY) {
         BlockVector3 dim = clipboard.getDimensions();
         byte[][] heightArray = new byte[dim.getBlockX()][dim.getBlockZ()];
-        int minX = clipboard.getMinimumPoint().getBlockX();
+        int clipMinX = clipboard.getMinimumPoint().getBlockX();
-        int minZ = clipboard.getMinimumPoint().getBlockZ();
+        int clipMinZ = clipboard.getMinimumPoint().getBlockZ();
-        int minY = clipboard.getMinimumPoint().getBlockY();
+        int clipMinY = clipboard.getMinimumPoint().getBlockY();
-        int maxY = clipboard.getMaximumPoint().getBlockY();
+        int clipMaxY = clipboard.getMaximumPoint().getBlockY();
-        int clipHeight = maxY - minY + 1;
+        int clipHeight = clipMaxY - clipMinY + 1;
         HashSet<IntPair> visited = new HashSet<>();
         MutableBlockVector3 bv = new MutableBlockVector3();
         for (BlockVector3 pos : clipboard.getRegion()) {
@@ -77,24 +83,24 @@ public class ScalableHeightMap implements HeightMap {
             visited.add(pair);
             int xx = pos.getBlockX();
             int zz = pos.getBlockZ();
-            int highestY = minY;
+            int highestY = clipMinY;
             bv.setComponents(pos);
-            for (int y = minY; y <= maxY; y++) {
+            for (int y = clipMinY; y <= clipMaxY; y++) {
                 bv.mutY(y);
                 BlockState block = clipboard.getBlock(bv);
                 if (!block.getBlockType().getMaterial().isAir()) {
                     highestY = y + 1;
                 }
             }
-            int pointHeight = Math.min(255, (256 * (highestY - minY)) / clipHeight);
+            int pointHeight = Math.min(clipMaxY, ((maxY - minY + 1 ) * (highestY - clipMinY)) / clipHeight);
-            int x = xx - minX;
+            int x = xx - clipMinX;
-            int z = zz - minZ;
+            int z = zz - clipMinZ;
             heightArray[x][z] = (byte) pointHeight;
         }
-        return new ArrayHeightMap(heightArray);
+        return new ArrayHeightMap(heightArray, minY, maxY);
     }
 
-    public static ScalableHeightMap fromPNG(InputStream stream) throws IOException {
+    public static ScalableHeightMap fromPNG(InputStream stream, int minY, int maxY) throws IOException {
         BufferedImage heightFile = MainUtil.readImage(stream);
         int width = heightFile.getWidth();
         int length = heightFile.getHeight();
@@ -113,7 +119,7 @@ public class ScalableHeightMap implements HeightMap {
                 array[x][z] = (byte) intensity;
             }
         }
-        return new ArrayHeightMap(array);
+        return new ArrayHeightMap(array, minY, maxY);
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/lighting/NMSRelighter.java

@@ -60,11 +60,12 @@ public class NMSRelighter implements Relighter {
     private final ConcurrentHashMap<Long, long[][][]> concurrentLightQueue;
     private final RelightMode relightMode;
     private final int maxY;
+    private final int minY;
     private final ReentrantLock lightingLock;
     private final AtomicBoolean finished = new AtomicBoolean(false);
     private boolean removeFirst;
 
-    public NMSRelighter(IQueueExtent<IQueueChunk> queue, boolean calculateHeightMaps) {
+    public NMSRelighter(IQueueExtent<IQueueChunk> queue) {
         this(queue, null);
     }
 
@@ -75,6 +76,7 @@ public class NMSRelighter implements Relighter {
         this.chunksToSend = new Long2ObjectOpenHashMap<>(12);
         this.concurrentLightQueue = new ConcurrentHashMap<>(12);
         this.maxY = queue.getMaxY();
+        this.minY = queue.getMinY();
         this.relightMode = relightMode != null ? relightMode : RelightMode.valueOf(Settings.IMP.LIGHTING.MODE);
         this.lightingLock = new ReentrantLock();
     }
@@ -118,6 +120,8 @@ public class NMSRelighter implements Relighter {
         if (m2 == null) {
             m2 = m1[x] = new long[4];
         }
+        // Account for negative y values by "adding" minY
+        y -= minY;
         m2[y >> 6] |= 1L << y;
     }
 
@@ -132,6 +136,8 @@ public class NMSRelighter implements Relighter {
                         this.lightQueue.put(index, currentMap);
                     }
                     set(x & 15, y, z & 15, currentMap);
+                    this.lightQueue.putAll(concurrentLightQueue);
+                    concurrentLightQueue.clear();
                 } finally {
                     lightLock.set(false);
                 }
@@ -154,7 +160,7 @@ public class NMSRelighter implements Relighter {
     }
 
     public boolean addChunk(int cx, int cz, byte[] fix, int bitmask) {
-        RelightSkyEntry toPut = new RelightSkyEntry(cx, cz, fix, bitmask);
+        RelightSkyEntry toPut = new RelightSkyEntry(cx, cz, fix, bitmask, minY, maxY);
         extendSkyToRelight.add(toPut);
         return true;
     }
@@ -188,7 +194,7 @@ public class NMSRelighter implements Relighter {
             if (!iChunk.isInit()) {
                 iChunk.init(queue, chunk.x, chunk.z);
             }
-            for (int i = 0; i < 16; i++) {
+            for (int i = minY >> 4; i <= maxY >> 4; i++) {
                 iChunk.removeSectionLighting(i, true);
             }
             iter.remove();
@@ -238,7 +244,7 @@ public class NMSRelighter implements Relighter {
                             for (int j = 0; j < 64; j++) {
                                 if (((value >> j) & 1) == 1) {
                                     int x = lx + bx;
-                                    int y = yStart + j;
+                                    int y = yStart + j + minY;
                                     int z = lz + bz;
                                     int oldLevel = iChunk.getEmittedLight(lx, y, lz);
                                     int newLevel = iChunk.getBrightness(lx, y, lz);
@@ -287,7 +293,7 @@ public class NMSRelighter implements Relighter {
                     removalVisited,
                     visited
             );
-            if (node.getY() > 0) {
+            if (node.getY() > minY) {
                 this.computeRemoveBlockLight(
                         node.getX(),
                         node.getY() - 1,
@@ -299,7 +305,7 @@ public class NMSRelighter implements Relighter {
                         visited
                 );
             }
-            if (node.getY() < 255) {
+            if (node.getY() < maxY) {
                 this.computeRemoveBlockLight(
                         node.getX(),
                         node.getY() + 1,
@@ -650,7 +656,7 @@ public class NMSRelighter implements Relighter {
             this.computeSpreadBlockLight(x, y - 1, z, currentLight, queue, visited);
         }
         state = this.queue.getBlock(x, y + 1, z);
-        if (y < 255 && !top && isSlabOrTrueValue(state, "top") && isStairOrTrueTop(state, true)) {
+        if (y < maxY && !top && isSlabOrTrueValue(state, "top") && isStairOrTrueTop(state, true)) {
             this.computeSpreadBlockLight(x, y + 1, z, currentLight, queue, visited);
         }
     }
@@ -696,7 +702,7 @@ public class NMSRelighter implements Relighter {
             this.computeSpreadBlockLight(x, y - 1, z, currentLight, queue, visited);
         }
         state = this.queue.getBlock(x, y + 1, z);
-        if (y < 255 && isSlabOrTrueValue(state, "top") && isStairOrTrueTop(state, false)) {
+        if (y < maxY && isSlabOrTrueValue(state, "top") && isStairOrTrueTop(state, false)) {
             this.computeSpreadBlockLight(x, y + 1, z, currentLight, queue, visited);
         }
     }
@@ -944,7 +950,7 @@ public class NMSRelighter implements Relighter {
                     int z = MathMan.unpairIntY(pair);
                     ChunkHolder<?> chunk = (ChunkHolder<?>) queue.getOrCreateChunk(x, z);
                     chunk.setBitMask(bitMask);
-                    chunk.flushLightToGet(true);
+                    chunk.flushLightToGet();
                     Fawe.imp().getPlatformAdapter().sendChunk(chunk.getOrCreateGet(), bitMask, true);
                     iter.remove();
                 }
@@ -984,7 +990,7 @@ public class NMSRelighter implements Relighter {
         }
     }
 
-    public void fill(byte[] mask, int chunkX, int y, int chunkZ, byte reason) {
+    public void fill(byte[] mask, ChunkHolder<?> iChunk, int y, byte reason) {
         if (y >= 16) {
             Arrays.fill(mask, (byte) 15);
             return;
@@ -995,12 +1001,10 @@ public class NMSRelighter implements Relighter {
                 return;
             }
             case SkipReason.AIR: {
-                int bx = chunkX << 4;
-                int bz = chunkZ << 4;
                 int index = 0;
                 for (int z = 0; z < 16; z++) {
                     for (int x = 0; x < 16; x++) {
-                        mask[index++] = (byte) queue.getSkyLight(bx + x, y, bz + z);
+                        mask[index++] = (byte) iChunk.getSkyLight(x, y, z);
                     }
                 }
             }
@@ -1026,19 +1030,19 @@ public class NMSRelighter implements Relighter {
                 }
             }
         }
-        for (int y = 255; y > 0; y--) {
+        for (int y = maxY; y > minY; y--) {
             for (RelightSkyEntry chunk : chunks) { // Propagate skylight
-                int layer = y >> 4;
+                int layer = (y - minY) >> 4;
                 byte[] mask = chunk.mask;
-                if (chunk.fix[layer] != SkipReason.NONE) {
-                    if ((y & 15) == 0 && layer != 0 && chunk.fix[layer - 1] == SkipReason.NONE) {
-                        fill(mask, chunk.x, y, chunk.z, chunk.fix[layer]);
-                    }
-                    continue;
-                }
                 int bx = chunk.x << 4;
                 int bz = chunk.z << 4;
                 ChunkHolder<?> iChunk = (ChunkHolder<?>) queue.getOrCreateChunk(chunk.x, chunk.z);
+                if (chunk.fix[layer] != SkipReason.NONE) {
+                    if ((y & 15) == 0 && layer != 0 && chunk.fix[layer - 1] == SkipReason.NONE) {
+                        fill(mask, iChunk, y, chunk.fix[layer]);
+                    }
+                    continue;
+                }
                 if (!iChunk.isInit()) {
                     iChunk.init(queue, chunk.x, chunk.z);
                 }
@@ -1157,29 +1161,29 @@ public class NMSRelighter implements Relighter {
                 }
                 byte value = mask[j];
                 if (x != 0 && z != 0) {
-                    if ((value = (byte) Math.max(iChunk.getSkyLight(x - 1, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunk.getSkyLight(x - 1, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunk.getSkyLight(x, y, z - 1) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunk.getSkyLight(x, y, z - 1) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else if (x == 0 && z == 0) {
-                    if ((value = (byte) Math.max(iChunkx.getSkyLight(15, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunkx.getSkyLight(15, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunkz.getSkyLight(x, y, 15) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunkz.getSkyLight(x, y, 15) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else if (x == 0) {
-                    if ((value = (byte) Math.max(iChunkx.getSkyLight(15, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunkx.getSkyLight(15, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunk.getSkyLight(x, y, z - 1) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunk.getSkyLight(x, y, z - 1) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else {
-                    if ((value = (byte) Math.max(iChunk.getSkyLight(x - 1, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunk.getSkyLight(x - 1, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunkz.getSkyLight(x, y, 15) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunkz.getSkyLight(x, y, 15) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
@@ -1203,29 +1207,29 @@ public class NMSRelighter implements Relighter {
                 }
                 byte value = mask[j];
                 if (x != 15 && z != 15) {
-                    if ((value = (byte) Math.max(iChunk.getSkyLight(x + 1, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunk.getSkyLight(x + 1, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunk.getSkyLight(x, y, z + 1) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunk.getSkyLight(x, y, z + 1) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else if (x == 15 && z == 15) {
-                    if ((value = (byte) Math.max(iChunkx.getSkyLight(0, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunkx.getSkyLight(0, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunkz.getSkyLight(x, y, 0) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunkz.getSkyLight(x, y, 0) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else if (x == 15) {
-                    if ((value = (byte) Math.max(iChunkx.getSkyLight(0, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunkx.getSkyLight(0, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunk.getSkyLight(x, y, z + 1) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunk.getSkyLight(x, y, z + 1) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
                     }
                 } else {
-                    if ((value = (byte) Math.max(iChunk.getSkyLight(x + 1, y, z) - 1, value)) >= 14) {
+                    if ((value = (byte) Math.max(iChunk.getSkyLight(x + 1, y, z) - 1, value)) < 14) {
-                    } else if ((value = (byte) Math.max(iChunkz.getSkyLight(x, y, 0) - 1, value)) >= 14) {
+                        value = (byte) Math.max(iChunkz.getSkyLight(x, y, 0) - 1, value);
                     }
                     if (value > mask[j]) {
                         iChunk.setSkyLight(x, y, z, mask[j] = value);
@@ -1235,7 +1239,7 @@ public class NMSRelighter implements Relighter {
         }
     }
 
-    private class RelightSkyEntry implements Comparable<RelightSkyEntry> {
+    private static class RelightSkyEntry implements Comparable<RelightSkyEntry> {
 
         public final int x;
         public final int z;
@@ -1244,7 +1248,7 @@ public class NMSRelighter implements Relighter {
         public int bitmask;
         public boolean smooth;
 
-        public RelightSkyEntry(int x, int z, byte[] fix, int bitmask) {
+        private RelightSkyEntry(int x, int z, byte[] fix, int bitmask, int minY, int maxY) {
             this.x = x;
             this.z = z;
             byte[] array = new byte[256];
@@ -1252,13 +1256,14 @@ public class NMSRelighter implements Relighter {
             this.mask = array;
             this.bitmask = bitmask;
             if (fix == null) {
-                this.fix = new byte[(maxY + 1) >> 4];
+                this.fix = new byte[(maxY - minY + 1) >> 4];
                 Arrays.fill(this.fix, SkipReason.NONE);
             } else {
                 this.fix = fix;
             }
         }
 
+        //Following are public because they are public in Object. NONE of this nested class is API.
         @Override
         public String toString() {
             return x + "," + z;

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/processor/lighting/RelightProcessor.java

@@ -28,11 +28,12 @@ public class RelightProcessor implements IBatchProcessor {
         if (Settings.IMP.LIGHTING.MODE == 2) {
             relighter.addChunk(chunk.getX(), chunk.getZ(), null, chunk.getBitMask());
         } else if (Settings.IMP.LIGHTING.MODE == 1) {
-            byte[] fix = new byte[16];
+            byte[] fix = new byte[get.getSectionCount()];
             boolean relight = false;
-            for (int i = 15; i >= 0; i--) {
+            for (int i = get.getMaxSectionIndex(); i >= get.getMinSectionIndex(); i--) {
                 if (!set.hasSection(i)) {
-                    fix[i] = Relighter.SkipReason.AIR;
+                    // Array index cannot be < 0 so "add" the min
+                    fix[i - get.getMinSectionIndex()] = Relighter.SkipReason.AIR;
                     continue;
                 }
                 relight = true;

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/generator/CavesGen.java

@@ -189,11 +189,11 @@ public class CavesGen extends GenBase {
                 n = 16;
             }
 
-            if (i1 < 1) {
+            if (i1 < chunk.getMinY() + 1) {
-                i1 = 1;
+                i1 = chunk.getMinY();
             }
-            if (i2 > 256 - 8) {
+            if (i2 >= chunk.getMaxY() - 8) {
-                i2 = 256 - 8;
+                i2 = chunk.getMaxY() - 8;
             }
             if (i3 < 0) {
                 i3 = 0;
@@ -207,7 +207,7 @@ public class CavesGen extends GenBase {
             for (int local_x = m; !waterFound && local_x < n; local_x++) {
                 for (int local_z = i3; !waterFound && local_z < i4; local_z++) {
                     for (int local_y = i2 + 1; !waterFound && local_y >= i1 - 1; local_y--) {
-                        if (local_y < 255) {
+                        if (local_y < chunk.getMaxY()) {
                             BlockState material = chunk.getBlock(bx + local_x, local_y, bz + local_z);
                             if (material.getBlockType() == BlockTypes.WATER) {
                                 waterFound = true;

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/generator/OreGen.java

@@ -78,11 +78,11 @@ public class OreGen implements Resource {
             double d12o2 = d12 * ONE_2;
 
             int minX = MathMan.floorZero(d7 - d11o2);
-            int minY = Math.max(1, MathMan.floorZero(d8 - d12o2));
+            int minY = Math.max(this.minY + 1, MathMan.floorZero(d8 - d12o2));
             int minZ = MathMan.floorZero(d9 - d11o2);
 
             int maxX = MathMan.floorZero(d7 + d11o2);
-            int maxY = Math.min(255, MathMan.floorZero(d8 + d12o2));
+            int maxY = Math.min(this.maxY, MathMan.floorZero(d8 + d12o2));
             int maxZ = MathMan.floorZero(d9 + d11o2);
 
             double id11o2 = 1.0 / (d11o2);

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/generator/SchemGen.java

@@ -33,7 +33,7 @@ public class SchemGen implements Resource {
     public boolean spawn(Random random, int x, int z) throws WorldEditException {
         mutable.mutX(x);
         mutable.mutZ(z);
-        int y = extent.getNearestSurfaceTerrainBlock(x, z, mutable.getBlockY(), 0, 255);
+        int y = extent.getNearestSurfaceTerrainBlock(x, z, mutable.getBlockY(), this.extent.getMinY(), this.extent.getMaxY());
         if (y == -1) {
             return false;
         }

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/AdjacentAnyMask.java

@@ -12,10 +12,14 @@ public class AdjacentAnyMask extends AbstractMask implements ResettableMask {
 
     private final CachedMask mask;
     private final MutableBlockVector3 mutable;
+    private final int minY;
+    private final int maxY;
 
-    public AdjacentAnyMask(Mask mask) {
+    public AdjacentAnyMask(Mask mask, int minY, int maxY) {
         this.mask = CachedMask.cache(mask);
         mutable = new MutableBlockVector3();
+        this.minY = minY;
+        this.maxY = maxY;
     }
 
     @Override
@@ -44,9 +48,9 @@ public class AdjacentAnyMask extends AbstractMask implements ResettableMask {
             return mutable.setComponents(0, 0, 1);
         } else if (mask.test(x, y, z - 1)) {
             return mutable.setComponents(0, 0, -1);
-        } else if (y < 256 && mask.test(x, y + 1, z)) {
+        } else if (y < maxY && mask.test(x, y + 1, z)) {
             return mutable.setComponents(0, 1, 0);
-        } else if (y > 0 && mask.test(x, y - 1, z)) {
+        } else if (y > minY && mask.test(x, y - 1, z)) {
             return mutable.setComponents(0, -1, 0);
         } else {
             return null;
@@ -55,7 +59,7 @@ public class AdjacentAnyMask extends AbstractMask implements ResettableMask {
 
     @Override
     public Mask copy() {
-        return new AdjacentAnyMask(mask.copy());
+        return new AdjacentAnyMask(mask.copy(), minY, maxY);
     }
 
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/AngleMask.java

@@ -18,6 +18,7 @@ public class AngleMask extends SolidBlockMask implements ResettableMask {
     protected final boolean overlay;
     protected final boolean checkFirst;
     protected final int maxY;
+    protected final int minY;
     protected final int distance;
 
     public AngleMask(Extent extent, double min, double max, boolean overlay, int distance) {
@@ -26,7 +27,8 @@ public class AngleMask extends SolidBlockMask implements ResettableMask {
         this.min = min;
         this.max = max;
         this.checkFirst = max >= (Math.tan(90 * (Math.PI / 180)));
-        this.maxY = extent.getMaximumPoint().getBlockY();
+        this.maxY = extent.getMaxY();
+        this.minY = extent.getMinY();
         this.overlay = overlay;
         this.distance = distance;
     }
@@ -77,7 +79,7 @@ public class AngleMask extends SolidBlockMask implements ResettableMask {
             }
             int result = cacheHeights[index] & 0xFF;
             if (y > result) {
-                cacheHeights[index] = (byte) (result = lastY = extent.getNearestSurfaceTerrainBlock(x, z, lastY, 0, maxY));
+                cacheHeights[index] = (byte) (result = lastY = extent.getNearestSurfaceTerrainBlock(x, z, lastY, minY, maxY));
             }
             return result;
         } catch (Throwable e) {
@@ -141,10 +143,10 @@ public class AngleMask extends SolidBlockMask implements ResettableMask {
         if (!mask.test(x, y, z - 1)) {
             return true;
         }
-        if (y < 255 && !mask.test(x, y + 1, z)) {
+        if (y < maxY && !mask.test(x, y + 1, z)) {
             return true;
         }
-        return y > 0 && !mask.test(x, y - 1, z);
+        return y > minY && !mask.test(x, y - 1, z);
     }
 
     @Override
@@ -164,7 +166,7 @@ public class AngleMask extends SolidBlockMask implements ResettableMask {
             return false;
         }
         if (overlay) {
-            if (y < 255 && !adjacentAir(vector)) {
+            if (y < maxY && !adjacentAir(vector)) {
                 return lastValue = false;
             }
         }

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/CachedMask.java

@@ -57,9 +57,10 @@ public class CachedMask extends AbstractDelegateMask implements ResettableMask {
             return result;
         } catch (UnsupportedOperationException ignored) {
             boolean result = getMask().test(mutable.setComponents(x, y, z));
-            if (y < 0 || y > 255) {
+            // Assume that the mask won't be given y outside the world range
-                return result;
+            // if (y < 0 || y > 255) {
-            }
+            //    return result;
+            //}
             resetCache();
             cache_checked.setOffset(x, z);
             cache_results.setOffset(x, z);

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/MaskedTargetBlock.java

@@ -25,10 +25,10 @@ public class MaskedTargetBlock extends TargetBlock {
             if (!mask.test(current.toBlockPoint())) {
                 if (searchForLastBlock) {
                     lastBlock = current;
-                    if (lastBlock.getBlockY() <= 0 || lastBlock.getBlockY() >= world.getMaxY()) {
+                    if (lastBlock.getBlockY() <= world.getMinY() || lastBlock.getBlockY() >= world.getMaxY()) {
                         searchForLastBlock = false;
                     }
-                } else if (current.getBlockY() <= 0) {
+                } else if (current.getBlockY() <= world.getMinY()) {
                     break;
                 }
             } else {

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/mask/SurfaceMask.java

@@ -9,7 +9,7 @@ import com.sk89q.worldedit.world.block.BlockTypes;
 public class SurfaceMask extends AdjacentAnyMask {
 
     public SurfaceMask(Extent extent) {
-        super(getMask(extent));
+        super(getMask(extent), extent.getMinY(), extent.getMaxY());
     }
 
     public static AbstractExtentMask getMask(Extent extent) {

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/AngleColorPattern.java

@@ -45,8 +45,8 @@ public class AngleColorPattern extends AnglePattern {
             int x = vector.getBlockX();
             int y = vector.getBlockY();
             int z = vector.getBlockZ();
-            int height = extent.getNearestSurfaceTerrainBlock(x, z, y, 0, maxY);
+            int height = extent.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY);
-            if (height > 0) {
+            if (height > minY) {
                 BlockState below = extent.getBlock(x, height - 1, z);
                 if (!below.getBlockType().getMaterial().isMovementBlocker()) {
                     return Integer.MAX_VALUE;

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/AnglePattern.java

@@ -13,6 +13,7 @@ public abstract class AnglePattern extends AbstractPattern {
     public final double factor;
     public final Extent extent;
     public final int maxY;
+    public final int minY;
     public final int distance;
 
     /**
@@ -23,9 +24,10 @@ public abstract class AnglePattern extends AbstractPattern {
      */
     public AnglePattern(Extent extent, int distance) {
         this.extent = new ExtentHeightCacher(extent);
-        this.maxY = extent.getMaximumPoint().getBlockY();
+        this.maxY = extent.getMaxY();
+        this.minY = extent.getMinY();
         this.distance = distance;
-        this.factor = (1D / distance) * (1D / 255);
+        this.factor = (1D / distance) * (1D / maxY);
     }
 
     public <T extends BlockStateHolder<T>> int getSlope(T block, BlockVector3 vector, Extent extent) {
@@ -36,29 +38,29 @@ public abstract class AnglePattern extends AbstractPattern {
             return -1;
         }
         int slope = Math.abs(
-                extent.getNearestSurfaceTerrainBlock(x + distance, z, y, 0, maxY) - extent
+                extent.getNearestSurfaceTerrainBlock(x + distance, z, y, minY, maxY) - extent
-                        .getNearestSurfaceTerrainBlock(x - distance, z, y, 0, maxY)) * 7;
+                        .getNearestSurfaceTerrainBlock(x - distance, z, y, minY, maxY)) * 7;
         slope += Math.abs(extent.getNearestSurfaceTerrainBlock(
                 x,
                 z + distance,
                 y,
-                0,
+                minY,
                 maxY
-        ) - extent.getNearestSurfaceTerrainBlock(x, z - distance, y, 0, maxY)) * 7;
+        ) - extent.getNearestSurfaceTerrainBlock(x, z - distance, y, minY, maxY)) * 7;
         slope += Math.abs(extent.getNearestSurfaceTerrainBlock(
                 x + distance,
                 z + distance,
                 y,
-                0,
+                minY,
                 maxY
-        ) - extent.getNearestSurfaceTerrainBlock(x - distance, z - distance, y, 0, maxY)) * 5;
+        ) - extent.getNearestSurfaceTerrainBlock(x - distance, z - distance, y, minY, maxY)) * 5;
         slope += Math.abs(extent.getNearestSurfaceTerrainBlock(
                 x - distance,
                 z + distance,
                 y,
-                0,
+                minY,
                 maxY
-        ) - extent.getNearestSurfaceTerrainBlock(x + distance, z - distance, y, 0, maxY)) * 5;
+        ) - extent.getNearestSurfaceTerrainBlock(x + distance, z - distance, y, minY, maxY)) * 5;
         return slope;
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/OffsetPattern.java

@@ -7,6 +7,7 @@ import com.sk89q.worldedit.function.pattern.AbstractPattern;
 import com.sk89q.worldedit.function.pattern.Pattern;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockTypes;
 
 public class OffsetPattern extends AbstractPattern {
 
@@ -42,6 +43,9 @@ public class OffsetPattern extends AbstractPattern {
         mutable.mutX(position.getX() + dx);
         mutable.mutY(position.getY() + dy);
         mutable.mutZ(position.getZ() + dz);
+        if (mutable.getY() < minY || mutable.getY() > maxY) {
+            return BlockTypes.AIR.getDefaultState().toBaseBlock();
+        }
         return pattern.applyBlock(mutable);
     }
 
@@ -49,10 +53,10 @@ public class OffsetPattern extends AbstractPattern {
     public boolean apply(Extent extent, BlockVector3 get, BlockVector3 set) throws WorldEditException {
         mutable.mutX(get.getX() + dx);
         mutable.mutY(get.getY() + dy);
-        if (mutable.getY() < minY || mutable.getY() > maxY) {
+        mutable.mutZ(get.getZ() + dz);
+        if (mutable.getY() < extent.getMinY() || mutable.getY() > extent.getMaxY()) {
             return false;
         }
-        mutable.mutZ(get.getZ() + dz);
         return pattern.apply(extent, get, mutable);
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/RandomOffsetPattern.java

@@ -7,6 +7,7 @@ import com.sk89q.worldedit.function.pattern.AbstractPattern;
 import com.sk89q.worldedit.function.pattern.Pattern;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockTypes;
 
 import java.util.SplittableRandom;
 
@@ -32,8 +33,8 @@ public class RandomOffsetPattern extends AbstractPattern {
      * @param dx      offset x
      * @param dy      offset y
      * @param dz      offset z
-     * @param minY    min applicable y (inclusive
+     * @param minY    min applicable y (inclusive)
-     * @param maxY    max applicable y (inclusive
+     * @param maxY    max applicable y (inclusive)
      */
     public RandomOffsetPattern(Pattern pattern, int dx, int dy, int dz, int minY, int maxY) {
         this.pattern = pattern;
@@ -54,6 +55,9 @@ public class RandomOffsetPattern extends AbstractPattern {
         mutable.mutX((position.getX() + r.nextInt(dx2) - dx));
         mutable.mutY((position.getY() + r.nextInt(dy2) - dy));
         mutable.mutZ((position.getZ() + r.nextInt(dz2) - dz));
+        if (mutable.getY() < minY || mutable.getY() > maxY) {
+            return BlockTypes.AIR.getDefaultState().toBaseBlock();
+        }
         return pattern.applyBlock(mutable);
     }
 
@@ -62,7 +66,7 @@ public class RandomOffsetPattern extends AbstractPattern {
         mutable.mutX((set.getX() + r.nextInt(dx2) - dx));
         mutable.mutY((set.getY() + r.nextInt(dy2) - dy));
         mutable.mutZ((set.getZ() + r.nextInt(dz2) - dz));
-        if (mutable.getY() < minY || mutable.getY() > maxY) {
+        if (mutable.getY() < extent.getMinY() || mutable.getY() > extent.getMaxY()) {
             return false;
         }
         return pattern.apply(extent, get, mutable);

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/RelativePattern.java

@@ -7,6 +7,7 @@ import com.sk89q.worldedit.function.pattern.AbstractPattern;
 import com.sk89q.worldedit.function.pattern.Pattern;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockTypes;
 
 public class RelativePattern extends AbstractPattern implements ResettablePattern {
 
@@ -37,6 +38,9 @@ public class RelativePattern extends AbstractPattern implements ResettablePatter
         mutable.mutX(pos.getX() - origin.getX());
         mutable.mutY(pos.getY() - origin.getY());
         mutable.mutZ(pos.getZ() - origin.getZ());
+        if (mutable.getY() < minY || mutable.getY() > maxY) {
+            return BlockTypes.AIR.getDefaultState().toBaseBlock();
+        }
         return pattern.applyBlock(mutable);
     }
 
@@ -47,10 +51,10 @@ public class RelativePattern extends AbstractPattern implements ResettablePatter
         }
         mutable.mutX(set.getX() - origin.getX());
         mutable.mutY(set.getY() - origin.getY());
-        if (mutable.getY() < minY || mutable.getY() > maxY) {
+        mutable.mutZ(set.getZ() - origin.getZ());
+        if (mutable.getY() < extent.getMinY() || mutable.getY() > extent.getMaxY()) {
             return false;
         }
-        mutable.mutZ(set.getZ() - origin.getZ());
         return pattern.apply(extent, get, mutable);
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/SolidRandomOffsetPattern.java

@@ -66,6 +66,12 @@ public class SolidRandomOffsetPattern extends AbstractPattern {
         mutable.mutX(position.getX() + r.nextInt(dx2) - dx);
         mutable.mutY(position.getY() + r.nextInt(dy2) - dy);
         mutable.mutZ(position.getZ() + r.nextInt(dz2) - dz);
+        if (mutable.getY() < minY || mutable.getY() > maxY) {
+            return BlockTypes.AIR.getDefaultState().toBaseBlock();
+        }
+        if (mutable.getY() < minY || mutable.getY() > maxY) {
+            return BlockTypes.AIR.getDefaultState().toBaseBlock();
+        }
         BaseBlock block = pattern.applyBlock(mutable);
         if (block.getMaterial().isSolid()) {
             return block;
@@ -77,10 +83,10 @@ public class SolidRandomOffsetPattern extends AbstractPattern {
     public boolean apply(Extent extent, BlockVector3 get, BlockVector3 set) throws WorldEditException {
         mutable.mutX(set.getX() + r.nextInt(dx2) - dx);
         mutable.mutY(set.getY() + r.nextInt(dy2) - dy);
-        if (mutable.getY() < minY || mutable.getY() > maxY) {
+        mutable.mutZ(set.getZ() + r.nextInt(dz2) - dz);
+        if (mutable.getY() < extent.getMinY() || mutable.getY() > extent.getMaxY()) {
             return false;
         }
-        mutable.mutZ(set.getZ() + r.nextInt(dz2) - dz);
         BaseBlock block = pattern.applyBlock(mutable);
         if (block.getMaterial().isSolid()) {
             return pattern.apply(extent, get, mutable);

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/pattern/SurfaceRandomOffsetPattern.java

@@ -1,6 +1,8 @@
 package com.fastasyncworldedit.core.function.pattern;
 
 import com.fastasyncworldedit.core.math.MutableBlockVector3;
+import com.sk89q.worldedit.WorldEditException;
+import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.function.pattern.AbstractPattern;
 import com.sk89q.worldedit.function.pattern.Pattern;
 import com.sk89q.worldedit.function.visitor.BreadthFirstSearch;
@@ -41,6 +43,11 @@ public class SurfaceRandomOffsetPattern extends AbstractPattern {
         allowed = new MutableBlockVector3[buffer.length];
     }
 
+    @Override
+    public boolean apply(final Extent extent, final BlockVector3 get, final BlockVector3 set) throws WorldEditException {
+        return super.apply(extent, get, set);
+    }
+
     @Override
     public BaseBlock applyBlock(BlockVector3 position) {
         return pattern.applyBlock(travel(position));

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/visitor/AboveVisitor.java

@@ -22,13 +22,12 @@ public class AboveVisitor extends RecursiveVisitor {
      * @param mask     the mask
      * @param function the function
      * @param baseY    the base Y
+     * @param depth    maximum number of iterations
+     * @param minY     min visitable y value. Inclusive.
+     * @param maxY     max visitable y value. Inclusive.
      */
-    public AboveVisitor(Mask mask, RegionFunction function, int baseY) {
+    public AboveVisitor(Mask mask, RegionFunction function, int baseY, int depth, int minY, int maxY) {
-        this(mask, function, baseY, Integer.MAX_VALUE);
+        super(mask, function, depth, minY, maxY);
-    }
-
-    public AboveVisitor(Mask mask, RegionFunction function, int baseY, int depth) {
-        super(mask, function, depth);
         checkNotNull(mask);
 
         this.baseY = baseY;

worldedit-core/src/main/java/com/fastasyncworldedit/core/function/visitor/DirectionalVisitor.java

@@ -19,12 +19,22 @@ public class DirectionalVisitor extends RecursiveVisitor {
     private final BlockVector3 origin;
     private final BlockVector3 dirVec;
 
-    public DirectionalVisitor(Mask mask, RegionFunction function, BlockVector3 origin, BlockVector3 direction) {
+    /**
-        this(mask, function, origin, direction, Integer.MAX_VALUE);
+     * New visitor. Only visits in the given direction
-    }
+     *
-
+     * @param mask      block mask
-    public DirectionalVisitor(Mask mask, RegionFunction function, BlockVector3 origin, BlockVector3 direction, int distance) {
+     * @param function  function to apply
-        super(mask, function, distance);
+     * @param origin    start position
+     * @param direction allowable direction to visit between
+     * @param distance  max number of iterations
+     * @param minY      min visitable y value. Inclusive.
+     * @param maxY      max visitable y value. Inclusive.
+     */
+    public DirectionalVisitor(
+            Mask mask, RegionFunction function, BlockVector3 origin, BlockVector3 direction, int distance,
+            int minY, int maxY
+    ) {
+        super(mask, function, distance, minY, maxY);
         checkNotNull(mask);
         this.origin = origin;
         this.dirVec = direction;

worldedit-core/src/main/java/com/fastasyncworldedit/core/history/DiskStorageHistory.java

@@ -102,6 +102,7 @@ public class DiskStorageHistory extends FaweStreamChangeSet {
         nbttFile = new File(folder, index + ".nbtt");
         entfFile = new File(folder, index + ".entf");
         enttFile = new File(folder, index + ".entt");
+        //Switch file ending due to new (sort-of) format. (Added e for Extended height)
         bdFile = new File(folder, index + ".bd");
         bioFile = new File(folder, index + ".bio");
     }
@@ -431,6 +432,8 @@ public class DiskStorageHistory extends FaweStreamChangeSet {
                 final FaweInputStream gis = MainUtil.getCompressedIS(fis);
                 // skip mode
                 gis.skipFully(1);
+                // skip version
+                gis.skipFully(1);
                 // origin
                 ox = ((gis.read() << 24) + (gis.read() << 16) + (gis.read() << 8) + gis.read());
                 oz = ((gis.read() << 24) + (gis.read() << 16) + (gis.read() << 8) + gis.read());

worldedit-core/src/main/java/com/fastasyncworldedit/core/history/changeset/AbstractChangeSet.java

@@ -157,7 +157,7 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
                 addEntityCreate(tag);
             }
         }
-        for (int layer = 0; layer < 16; layer++) {
+        for (int layer = get.getMinSectionIndex(); layer <= get.getMaxSectionIndex(); layer++) {
             if (!set.hasSection(layer)) {
                 continue;
             }
@@ -172,6 +172,7 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
             char[] blocksSet;
             System.arraycopy(set.load(layer), 0, (blocksSet = new char[4096]), 0, 4096);
 
+            // Account for negative layers
             int by = layer << 4;
             for (int y = 0, index = 0; y < 16; y++) {
                 int yy = y + by;
@@ -195,14 +196,21 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
 
         BiomeType[] biomes = set.getBiomes();
         if (biomes != null) {
-            for (int y = 0, index = 0; y < 64; y++) {
+            int index = 0;
-                for (int z = 0; z < 4; z++) {
+            for (int layer = get.getMinSectionIndex(); layer <= get.getMaxSectionIndex(); layer++) {
-                    for (int x = 0; x < 4; x++, index++) {
+                if (!set.hasBiomes(layer)) {
-                        BiomeType newBiome = biomes[index];
+                    continue;
-                        if (newBiome != null) {
+                }
-                            BiomeType oldBiome = get.getBiomeType(x, y, z);
+                int yy = layer << 4;
-                            if (oldBiome != newBiome) {
+                for (int y = 0; y < 4; y++) {
-                                addBiomeChange(bx + (x << 2), y << 2, bz + (z << 2), oldBiome, newBiome);
+                    for (int z = 0; z < 4; z++) {
+                        for (int x = 0; x < 4; x++, index++) {
+                            BiomeType newBiome = biomes[index];
+                            if (newBiome != null) {
+                                BiomeType oldBiome = get.getBiomeType(x, y, z);
+                                if (oldBiome != newBiome) {
+                                    addBiomeChange(bx + (x << 2), yy + (y << 2), bz + (z << 2), oldBiome, newBiome);
+                                }
                             }
                         }
                     }
@@ -341,11 +349,17 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
         return addWriteTask(writeTask, Fawe.isMainThread());
     }
 
-    public Future<?> addWriteTask(Runnable writeTask, boolean completeNow) {
+    public Future<?> addWriteTask(final Runnable writeTask, final boolean completeNow) {
         AbstractChangeSet.this.waitingCombined.incrementAndGet();
         Runnable wrappedTask = () -> {
             try {
                 writeTask.run();
+            } catch (Throwable t) {
+                if (completeNow) {
+                    throw t;
+                } else {
+                    t.printStackTrace();
+                }
             } finally {
                 if (AbstractChangeSet.this.waitingCombined.decrementAndGet() <= 0) {
                     synchronized (AbstractChangeSet.this.waitingAsync) {

worldedit-core/src/main/java/com/fastasyncworldedit/core/history/changeset/FaweStreamChangeSet.java

@@ -28,11 +28,16 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
+/**
+ * FAWE stream ChangeSet offering support for extended-height worlds
+ */
 public abstract class FaweStreamChangeSet extends AbstractChangeSet {
 
     public static final int HEADER_SIZE = 9;
+    private static final int version = 1;
     private int mode;
     private final int compression;
+    private final int minY;
 
     protected FaweStreamIdDelegate idDel;
     protected FaweStreamPositionDelegate posDel;
@@ -44,6 +49,7 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
     public FaweStreamChangeSet(World world, int compression, boolean storeRedo, boolean smallLoc) {
         super(world);
         this.compression = compression;
+        this.minY = world.getMinY();
         init(storeRedo, smallLoc);
     }
 
@@ -139,6 +145,10 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
 
                 @Override
                 public void write(OutputStream out, int x, int y, int z) throws IOException {
+                    if (y < 0 || y > 255) {
+                        throw new UnsupportedOperationException("y cannot be outside range 0-255 for " +
+                                "small-edits=true");
+                    }
                     int rx = -lx + (lx = x);
                     int ry = -ly + (ly = y);
                     int rz = -lz + (lz = z);
@@ -174,7 +184,7 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
             };
         } else {
             posDel = new FaweStreamPositionDelegate() {
-                final byte[] buffer = new byte[5];
+                final byte[] buffer = new byte[6];
                 int lx;
                 int ly;
                 int lz;
@@ -188,7 +198,8 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
                     stream.write(((rx) >> 8) & 0xff);
                     stream.write((rz) & 0xff);
                     stream.write(((rz) >> 8) & 0xff);
-                    stream.write((byte) ry);
+                    stream.write((ry) & 0xff);
+                    stream.write(((ry) >> 8) & 0xff);
                 }
 
                 @Override
@@ -199,7 +210,7 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
 
                 @Override
                 public int readY(FaweInputStream is) throws IOException {
-                    return (ly = (ly + (buffer[4]))) & 0xFF;
+                    return ly = (ly + (buffer[4] & 0xFF) + (buffer[5] << 8));
                 }
 
                 @Override
@@ -212,6 +223,8 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
 
     public void writeHeader(OutputStream os, int x, int y, int z) throws IOException {
         os.write(mode);
+        // Allows for version detection of history in case of changes to format.
+        os.write(version);
         setOrigin(x, z);
         os.write((byte) (x >> 24));
         os.write((byte) (x >> 16));
@@ -227,6 +240,10 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
     public void readHeader(InputStream is) throws IOException {
         // skip mode
         int mode = is.read();
+        int version = is.read();
+        if (version != FaweStreamChangeSet.version) {
+            throw new UnsupportedOperationException(String.format("Version %s history not supported!", version));
+        }
         // origin
         int x = ((is.read() << 24) + (is.read() << 16) + (is.read() << 8) + is.read());
         int z = ((is.read() << 24) + (is.read() << 16) + (is.read() << 8) + is.read());
@@ -290,10 +307,6 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
     public abstract NBTInputStream getTileRemoveIS() throws IOException;
 
     protected int blockSize;
-    public int entityCreateSize;
-    public int entityRemoveSize;
-    public int tileCreateSize;
-    public int tileRemoveSize;
 
     private int originX;
     private int originZ;
@@ -325,9 +338,12 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
     }
 
     @Override
-    public void addBiomeChange(int x, int y, int z, BiomeType from, BiomeType to) {
+    public void addBiomeChange(int bx, int by, int bz, BiomeType from, BiomeType to) {
         blockSize++;
         try {
+            int x = bx >> 2;
+            int y = by >> 2;
+            int z = bz >> 2;
             FaweOutputStream os = getBiomeOS();
             os.write((byte) (x >> 24));
             os.write((byte) (x >> 16));
@@ -337,7 +353,9 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
             os.write((byte) (z >> 16));
             os.write((byte) (z >> 8));
             os.write((byte) (z));
-            os.write((byte) (y));
+            // only need to store biomes in the 4x4x4 chunks so only need one byte for y still (signed byte -128 -> 127)
+            //  means -512 -> 508. Add 128 to avoid negative value casting.
+            os.write((byte) (y + 128));
             os.writeVarInt(from.getInternalId());
             os.writeVarInt(to.getInternalId());
         } catch (Throwable e) {
@@ -465,9 +483,9 @@ public abstract class FaweStreamChangeSet extends AbstractChangeSet {
                 try {
                     int int1 = is.read();
                     if (int1 != -1) {
-                        int x = ((int1 << 24) + (is.read() << 16) + (is.read() << 8) + is.read());
+                        int x = ((int1 << 24) + (is.read() << 16) + (is.read() << 8) + is.read()) << 2;
-                        int z = ((is.read() << 24) + (is.read() << 16) + (is.read() << 8) + is.read());
+                        int z = ((is.read() << 24) + (is.read() << 16) + (is.read() << 8) + is.read()) << 2;
-                        int y = is.read();
+                        int y = (is.read() - 128) << 2;
                         int from = is.readVarInt();
                         int to = is.readVarInt();
                         change.setBiome(x, y, z, from, to);

worldedit-core/src/main/java/com/fastasyncworldedit/core/math/BlockVector3ChunkMap.java

@@ -3,26 +3,26 @@ package com.fastasyncworldedit.core.math;
 import com.fastasyncworldedit.core.util.MathMan;
 import com.fastasyncworldedit.core.util.collection.IAdaptedMap;
 import com.sk89q.worldedit.math.BlockVector3;
-import it.unimi.dsi.fastutil.shorts.Short2ObjectArrayMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectArrayMap;
 
 import java.util.Map;
 
-public class BlockVector3ChunkMap<T> implements IAdaptedMap<BlockVector3, T, Short, T> {
+public class BlockVector3ChunkMap<T> implements IAdaptedMap<BlockVector3, T, Integer, T> {
 
-    private final Short2ObjectArrayMap<T> map = new Short2ObjectArrayMap<>();
+    private final Int2ObjectArrayMap<T> map = new Int2ObjectArrayMap<>();
 
     @Override
-    public Map<Short, T> getParent() {
+    public Map<Integer, T> getParent() {
         return map;
     }
 
     @Override
-    public Short adaptKey(BlockVector3 key) {
+    public Integer adaptKey(BlockVector3 key) {
         return MathMan.tripleBlockCoord(key.getX(), key.getY(), key.getZ());
     }
 
     @Override
-    public BlockVector3 adaptKey2(Short key) {
+    public BlockVector3 adaptKey2(Integer key) {
         int x = MathMan.untripleBlockCoordX(key);
         int y = MathMan.untripleBlockCoordY(key);
         int z = MathMan.untripleBlockCoordZ(key);
@@ -40,23 +40,23 @@ public class BlockVector3ChunkMap<T> implements IAdaptedMap<BlockVector3, T, Sho
     }
 
     public T put(int x, int y, int z, T value) {
-        short key = MathMan.tripleBlockCoord(x, y, z);
+        int key = MathMan.tripleBlockCoord(x, y, z);
         return map.put(key, value);
     }
 
 
     public T get(int x, int y, int z) {
-        short key = MathMan.tripleBlockCoord(x, y, z);
+        int key = MathMan.tripleBlockCoord(x, y, z);
         return map.get(key);
     }
 
     public T remove(int x, int y, int z) {
-        short key = MathMan.tripleBlockCoord(x, y, z);
+        int key = MathMan.tripleBlockCoord(x, y, z);
         return map.remove(key);
     }
 
     public boolean contains(int x, int y, int z) {
-        short key = MathMan.tripleBlockCoord(x, y, z);
+        int key = MathMan.tripleBlockCoord(x, y, z);
         return map.containsKey(key);
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/math/BlockVectorSet.java

@@ -44,14 +44,14 @@ public class BlockVectorSet extends AbstractCollection<BlockVector3> implements
             int newSize = count + size;
             if (newSize > index) {
                 int localIndex = index - count;
-                BlockVector3 pos = set.getIndex(localIndex);
+                MutableBlockVector3 pos = set.getIndex(localIndex);
                 if (pos != null) {
                     int pair = entry.getIntKey();
                     int cx = MathMan.unpairX(pair);
                     int cz = MathMan.unpairY(pair);
-                    pos = pos.mutX((cx << 11) + pos.getBlockX());
+                    pos.mutX((cx << 11) + pos.getBlockX());
-                    pos = pos.mutZ((cz << 11) + pos.getBlockZ());
+                    pos.mutZ((cz << 11) + pos.getBlockZ());
-                    return pos;
+                    return pos.toImmutable();
                 }
             }
             count += newSize;
@@ -91,7 +91,7 @@ public class BlockVectorSet extends AbstractCollection<BlockVector3> implements
         if (!entries.hasNext()) {
             return Collections.emptyIterator();
         }
-        return new Iterator<BlockVector3>() {
+        return new Iterator<>() {
             Int2ObjectMap.Entry<LocalBlockVectorSet> entry = entries.next();
             Iterator<BlockVector3> entryIter = entry.getValue().iterator();
             final MutableBlockVector3 mutable = new MutableBlockVector3();

worldedit-core/src/main/java/com/fastasyncworldedit/core/math/LocalBlockVectorSet.java

@@ -11,14 +11,14 @@ import java.util.Set;
 
 /**
  * The LocalBlockVectorSet is a Memory and CPU optimized Set for storing BlockVectors which are all in a local region
- * - All vectors must be in a 2048 * 2048 area centered around the first entry
+ * - All vectors must be in a 2048 * 512 * 2048 area centered around the first entry
  * - This will use 8 bytes for every 64 BlockVectors (about 800x less than a HashSet)
  */
 public class LocalBlockVectorSet implements Set<BlockVector3> {
 
+    private final SparseBitSet set;
     private int offsetX;
     private int offsetZ;
-    private final SparseBitSet set;
 
     public LocalBlockVectorSet() {
         offsetX = offsetZ = Integer.MAX_VALUE;
@@ -42,7 +42,8 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
     }
 
     public boolean contains(int x, int y, int z) {
-        return set.get(MathMan.tripleSearchCoords(x - offsetX, y, z - offsetZ));
+        // take 128 to fit -256<y<255
+        return set.get(MathMan.tripleSearchCoords(x - offsetX, y - 128, z - offsetZ));
     }
 
     @Override
@@ -67,12 +68,15 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         if (size() < length * length * length) {
             int index = -1;
             while ((index = set.nextSetBit(index + 1)) != -1) {
-                int b1 = (byte) (index >> 0) & 0xFF;
+                int b1 = (index & 0xFF);
-                int b2 = (byte) (index >> 8) & 0x7F;
+                int b2 = (index >> 8) & 0xff;
-                int b3 = (byte) (index >> 15) & 0xFF;
+                int b3 = (index >> 15) & 0xFF;
-                int b4 = (byte) (index >> 23) & 0xFF;
+                int b4 = (index >> 23) & 0xFF;
-                if (Math.abs((offsetX + (((b3 + ((MathMan.unpair8x(b2)) << 8)) << 21) >> 21)) - x) <= radius && Math.abs((offsetZ + (((b4 + ((MathMan
+                int ix = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-                        .unpair8y(b2)) << 8)) << 21) >> 21)) - z) <= radius && Math.abs((b1) - y) <= radius) {
+                // Add 128 as we shift y by 128 to fit -256<y<255
+                int iy = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+                int iz = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+                if (Math.abs(ix - x) <= radius && Math.abs(iz - z) <= radius && Math.abs(iy - y) <= radius) {
                     return true;
                 }
             }
@@ -100,7 +104,7 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         this.offsetZ = z;
     }
 
-    protected BlockVector3 getIndex(int getIndex) {
+    protected MutableBlockVector3 getIndex(int getIndex) {
         int size = size();
         if (getIndex > size) {
             return null;
@@ -110,13 +114,15 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
             index = set.nextSetBit(index + 1);
         }
         if (index != -1) {
-            int b1 = (byte) (index >> 0) & 0xFF;
+            int b1 = (index & 0xFF);
-            int b2 = (byte) (index >> 8) & 0x7F;
+            int b2 = (index >> 8) & 0xff;
-            int b3 = (byte) (index >> 15) & 0xFF;
+            int b3 = (index >> 15) & 0xFF;
-            int b4 = (byte) (index >> 23) & 0xFF;
+            int b4 = (index >> 23) & 0xFF;
-            int x = offsetX + (((b3 + (MathMan.unpair8x(b2) << 8)) << 21) >> 21);
+            int x = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-            int z = offsetZ + (((b4 + (MathMan.unpair8y(b2) << 8)) << 21) >> 21);
+            // Add 128 as we shift y by 128 to fit -256<y<255
-            return MutableBlockVector3.get(x, b1, z);
+            int y = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+            int z = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+            return MutableBlockVector3.get(x, y, z);
         }
         return null;
     }
@@ -125,9 +131,9 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
     @Override
     public Iterator<BlockVector3> iterator() {
         return new Iterator<BlockVector3>() {
+            final MutableBlockVector3 mutable = new MutableBlockVector3(0, 0, 0);
             int index = set.nextSetBit(0);
             int previous = -1;
-            final MutableBlockVector3 mutable = new MutableBlockVector3(0, 0, 0);
 
             @Override
             public void remove() {
@@ -143,12 +149,16 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
             public BlockVector3 next() {
                 if (index != -1) {
                     int b1 = (index & 0xFF);
-                    int b2 = ((byte) (index >> 8)) & 0x7F;
+                    int b2 = (index >> 8) & 0xff;
-                    int b3 = ((byte) (index >> 15)) & 0xFF;
+                    int b3 = (index >> 15) & 0xFF;
-                    int b4 = ((byte) (index >> 23)) & 0xFF;
+                    int b4 = (index >> 23) & 0xFF;
-                    mutable.mutX(offsetX + (((b3 + (MathMan.unpair8x(b2) << 8)) << 21) >> 21));
+                    int x = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-                    mutable.mutY(b1);
+                    // Add 128 as we shift y by 128 to fit -256<y<255
-                    mutable.mutZ(offsetZ + (((b4 + (MathMan.unpair8y(b2) << 8)) << 21) >> 21));
+                    int y = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+                    int z = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+                    mutable.mutX(x);
+                    mutable.mutY(y);
+                    mutable.mutZ(z);
                     previous = index;
                     index = set.nextSetBit(index + 1);
                     return mutable;
@@ -175,12 +185,14 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         for (int i = 0; i < size; i++) {
             index = set.nextSetBit(index);
             int b1 = (index & 0xFF);
-            int b2 = ((byte) (index >> 8)) & 0x7F;
+            int b2 = (index >> 8) & 0xff;
-            int b3 = ((byte) (index >> 15)) & 0xFF;
+            int b3 = (index >> 15) & 0xFF;
-            int b4 = ((byte) (index >> 23)) & 0xFF;
+            int b4 = (index >> 23) & 0xFF;
-            int x = offsetX + (((b3 + ((MathMan.unpair8x(b2)) << 8)) << 21) >> 21);
+            int x = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-            int z = offsetZ + (((b4 + ((MathMan.unpair8y(b2)) << 8)) << 21) >> 21);
+            // Add 128 as we shift y by 128 to fit -256<y<255
-            array[i] = (T) BlockVector3.at(x, b1, z);
+            int y = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+            int z = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+            array[i] = (T) BlockVector3.at(x, y, z);
             index++;
         }
         return array;
@@ -195,7 +207,7 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         if (relX > 1023 || relX < -1024 || relZ > 1023 || relZ < -1024) {
             return false;
         }
-        return y >= 0 && y <= 256;
+        return y >= -128 && y <= 383;
     }
 
     public boolean add(int x, int y, int z) {
@@ -209,8 +221,8 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
             throw new UnsupportedOperationException(
                     "LocalVectorSet can only contain vectors within 1024 blocks (cuboid) of the first entry. ");
         }
-        if (y < 0 || y > 255) {
+        if (y < -128 || y > 383) {
-            throw new UnsupportedOperationException("LocalVectorSet can only contain vectors from y elem:[0,255]");
+            throw new UnsupportedOperationException("LocalVectorSet can only contain vectors from y elem:[-128,383]");
         }
         int index = getIndex(x, y, z);
         if (set.get(index)) {
@@ -227,11 +239,17 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
     }
 
     private int getIndex(BlockVector3 vector) {
-        return MathMan.tripleSearchCoords(vector.getBlockX() - offsetX, vector.getBlockY(), vector.getBlockZ() - offsetZ);
+        // take 128 to fit -256<y<255
+        return MathMan.tripleSearchCoords(
+                vector.getBlockX() - offsetX,
+                vector.getBlockY() - 128,
+                vector.getBlockZ() - offsetZ
+        );
     }
 
     private int getIndex(int x, int y, int z) {
-        return MathMan.tripleSearchCoords(x - offsetX, y, z - offsetZ);
+        // take 128 to fit -256<y<255
+        return MathMan.tripleSearchCoords(x - offsetX, y - 128, z - offsetZ);
     }
 
     public boolean remove(int x, int y, int z) {
@@ -240,7 +258,8 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         if (relX > 1023 || relX < -1024 || relZ > 1023 || relZ < -1024) {
             return false;
         }
-        int index = MathMan.tripleSearchCoords(relX, y, relZ);
+        // take 128 to fit -256<y<255
+        int index = MathMan.tripleSearchCoords(relX, y - 128, relZ);
         boolean value = set.get(index);
         set.clear(index);
         return value;
@@ -283,12 +302,16 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         for (int i = 0; i < size; i++) {
             index = set.nextSetBit(index + 1);
             int b1 = (index & 0xFF);
-            int b2 = ((byte) (index >> 8)) & 0x7F;
+            int b2 = (index >> 8) & 0xff;
-            int b3 = ((byte) (index >> 15)) & 0xFF;
+            int b3 = (index >> 15) & 0xFF;
-            int b4 = ((byte) (index >> 23)) & 0xFF;
+            int b4 = (index >> 23) & 0xFF;
-            mVec.mutX(offsetX + (((b3 + ((MathMan.unpair8x(b2)) << 8)) << 21) >> 21));
+            int x = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-            mVec.mutY(b1);
+            // Add 128 as we shift y by 128 to fit -256<y<255
-            mVec.mutZ(offsetZ + (((b4 + ((MathMan.unpair8y(b2)) << 8)) << 21) >> 21));
+            int y = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+            int z = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+            mVec.mutX(x);
+            mVec.mutY(y);
+            mVec.mutZ(z);
             if (!c.contains(mVec)) {
                 result = true;
                 set.clear(index);
@@ -312,21 +335,17 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         for (int i = 0; i < size; i++) {
             index = set.nextSetBit(index + 1);
             int b1 = (index & 0xFF);
-            int b2 = ((byte) (index >> 8)) & 0x7F;
+            int b2 = (index >> 8) & 0xff;
-            int b3 = ((byte) (index >> 15)) & 0xFF;
+            int b3 = (index >> 15) & 0xFF;
-            int b4 = ((byte) (index >> 23)) & 0xFF;
+            int b4 = (index >> 23) & 0xFF;
-            int x = offsetX + (((b3 + ((MathMan.unpair8x(b2)) << 8)) << 21) >> 21);
+            int x = (offsetX + (b3 + (((b2 & 0x7)) << 8)) << 21) >> 21;
-            int z = offsetZ + (((b4 + ((MathMan.unpair8y(b2)) << 8)) << 21) >> 21);
+            // Add 128 as we shift y by 128 to fit -256<y<255
-            visitor.run(x, b1, z, index);
+            int y = 128 + b1 * (((b2 >> 6) & 0x1) == 0 ? 1 : -1);
+            int z = (offsetZ + (b4 + (((b2 >> 3) & 0x7) << 8)) << 21) >> 21;
+            visitor.run(x, y, z, index);
         }
     }
 
-    public interface BlockVectorSetVisitor {
-
-        void run(int x, int y, int z, int index);
-
-    }
-
     @Override
     public void clear() {
         offsetZ = Integer.MAX_VALUE;
@@ -334,4 +353,10 @@ public class LocalBlockVectorSet implements Set<BlockVector3> {
         set.clear();
     }
 
+    public interface BlockVectorSetVisitor {
+
+        void run(int x, int y, int z, int index);
+
+    }
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/IBatchProcessor.java

@@ -1,6 +1,5 @@
 package com.fastasyncworldedit.core.queue;
 
-import com.fastasyncworldedit.core.FaweCache;
 import com.fastasyncworldedit.core.extent.processor.EmptyBatchProcessor;
 import com.fastasyncworldedit.core.extent.processor.MultiBatchProcessor;
 import com.fastasyncworldedit.core.extent.processor.ProcessorScope;
@@ -42,7 +41,7 @@ public interface IBatchProcessor {
      */
     default boolean trimY(IChunkSet set, int minY, int maxY) {
         int minLayer = (minY - 1) >> 4;
-        for (int layer = 0; layer <= minLayer; layer++) {
+        for (int layer = set.getMinSectionIndex(); layer <= minLayer; layer++) {
             if (set.hasSection(layer)) {
                 if (layer == minLayer) {
                     char[] arr = set.load(layer);
@@ -57,7 +56,7 @@ public interface IBatchProcessor {
             }
         }
         int maxLayer = (maxY + 1) >> 4;
-        for (int layer = maxLayer; layer < FaweCache.IMP.CHUNK_LAYERS; layer++) {
+        for (int layer = maxLayer; layer < set.getMaxSectionIndex(); layer++) {
             if (set.hasSection(layer)) {
                 if (layer == minLayer) {
                     char[] arr = set.load(layer);
@@ -74,10 +73,8 @@ public interface IBatchProcessor {
         try {
             int layer = (minY - 15) >> 4;
             while (layer < (maxY + 15) >> 4) {
-                if (layer > -1) {
+                if (set.hasSection(layer)) {
-                    if (set.hasSection(layer)) {
+                    return true;
-                        return true;
-                    }
                 }
                 layer++;
             }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/IBlocks.java

@@ -11,7 +11,6 @@ import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.registry.BlockRegistry;
-import org.jetbrains.annotations.Range;
 
 import java.io.IOException;
 import java.util.Map;
@@ -23,7 +22,14 @@ import java.util.stream.IntStream;
  */
 public interface IBlocks extends Trimable {
 
-    boolean hasSection(@Range(from = 0, to = 15) int layer);
+    /**
+     * Returns if the chunk has a BLOCKS section at the given layer. May not be indicative of presence
+     * of entities, tile entites, biomes, etc.
+     *
+     * @param layer chunk section layer
+     * @return if blocks/a block section is present
+     */
+    boolean hasSection(int layer);
 
     char[] load(int layer);
 
@@ -38,7 +44,7 @@ public interface IBlocks extends Trimable {
     BiomeType getBiomeType(int x, int y, int z);
 
     default int getBitMask() {
-        return IntStream.range(0, FaweCache.IMP.CHUNK_LAYERS).filter(this::hasSection)
+        return IntStream.range(getMinSectionIndex(), getMaxSectionIndex() + 1).filter(this::hasSection)
                 .map(layer -> (1 << layer)).sum();
     }
 
@@ -48,6 +54,21 @@ public interface IBlocks extends Trimable {
 
     IBlocks reset();
 
+    /**
+     * Get the number of stores sections
+     */
+    int getSectionCount();
+
+    /**
+     * Max ChunkSection array index
+     */
+    int getMaxSectionIndex();
+
+    /**
+     * Min ChunkSection array index
+     */
+    int getMinSectionIndex();
+
     default byte[] toByteArray(boolean full, boolean stretched) {
         return toByteArray(null, getBitMask(), full, stretched);
     }
@@ -61,7 +82,7 @@ public interface IBlocks extends Trimable {
                 .queryCapability(Capability.GAME_HOOKS).getRegistries().getBlockRegistry();
         FastByteArrayOutputStream sectionByteArray = new FastByteArrayOutputStream(buffer);
         try (FaweOutputStream sectionWriter = new FaweOutputStream(sectionByteArray)) {
-            for (int layer = 0; layer < FaweCache.IMP.CHUNK_LAYERS; layer++) {
+            for (int layer = 0; layer < this.getSectionCount(); layer++) {
                 if (!this.hasSection(layer) || (bitMask & (1 << layer)) == 0) {
                     continue;
                 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/IChunkExtent.java

@@ -17,7 +17,6 @@ import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
-import org.jetbrains.annotations.Range;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -37,7 +36,7 @@ public interface IChunkExtent<T extends IChunk> extends Extent {
     T getOrCreateChunk(int chunkX, int chunkZ);
 
     @Override
-    default <B extends BlockStateHolder<B>> boolean setBlock(int x, @Range(from = 0, to = 255) int y, int z, B state) {
+    default <B extends BlockStateHolder<B>> boolean setBlock(int x, int y, int z, B state) {
         final IChunk chunk = getOrCreateChunk(x >> 4, z >> 4);
         return chunk.setBlock(x & 15, y, z & 15, state);
     }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/IChunkGet.java

@@ -48,19 +48,43 @@ public interface IChunkGet extends IBlocks, Trimable, InputExtent, ITileInput {
 
     CompoundTag getEntity(UUID uuid);
 
-    void setCreateCopy(boolean createCopy);
-
     boolean isCreateCopy();
 
+    void setCreateCopy(boolean createCopy);
+
     @Nullable
     default IChunkGet getCopy() {
         return null;
     }
 
-    void setLightingToGet(char[][] lighting);
+    /**
+     * Flush the block lighting array (section*blocks) to the chunk GET between the given section indices. Negative allowed.
+     *
+     * @param lighting          lighting array
+     * @param startSectionIndex lowest section index
+     * @param endSectionIndex   highest section index
+     */
+    void setLightingToGet(char[][] lighting, int startSectionIndex, int endSectionIndex);
 
-    void setSkyLightingToGet(char[][] lighting);
+    /**
+     * Flush the sky lighting array (section*blocks) to the chunk GET between the given section indices. Negative allowed.
+     *
+     * @param lighting          sky lighting array
+     * @param startSectionIndex lowest section index
+     * @param endSectionIndex   highest section index
+     */
+    void setSkyLightingToGet(char[][] lighting, int startSectionIndex, int endSectionIndex);
 
     void setHeightmapToGet(HeightMapType type, int[] data);
 
+    /**
+     * Max y value for the chunk's world (inclusive)
+     */
+    int getMaxY();
+
+    /**
+     * Min y value for the chunk's world (inclusive)
+     */
+    int getMinY();
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/IChunkSet.java

@@ -107,4 +107,12 @@ public interface IChunkSet extends IBlocks, OutputExtent {
         return null;
     }
 
+    /**
+     * If the given layer has biomes stored to be set to the world. Can be negative
+     *
+     * @param layer layer to check
+     * @return if the layer has biomes stored to be set to the world
+     */
+    boolean hasBiomes(int layer);
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/Flood.java

@@ -25,11 +25,17 @@ public class Flood {
     private int chunkYLayer;
     private int chunkZ;
     private final ConcurrentLinkedQueue<int[]> queuePool = new ConcurrentLinkedQueue<>();
+    private final int minSectionIndex;
+    private final int maxSectionIndex;
+    private final int sectionCount;
 
-    public Flood(int maxBranch, int maxDepth, Direction[] directions) {
+    public Flood(int maxBranch, int maxDepth, Direction[] directions, int minSectionIndex, int maxSectionIndex) {
         this.maxBranch = maxBranch;
         this.maxDepth = maxDepth;
         this.directions = directions;
+        this.minSectionIndex = minSectionIndex;
+        this.maxSectionIndex = maxSectionIndex;
+        this.sectionCount = maxSectionIndex - minSectionIndex + 1;
 
         this.queues = new int[27][];
         this.visits = new long[27][];
@@ -64,7 +70,7 @@ public class Flood {
         int chunkX = x >> 4;
         int chunkZ = z >> 4;
         long pair = MathMan.pairInt(chunkX, chunkZ);
-        int layer = y >> 4;
+        int layer = (y >> 4) - minSectionIndex;
         int[] section = getOrCreateQueue(pair, layer);
         int val = (x & 15) + ((z & 15) << 4) + ((y & 15) << 8) + (depth << 12);
         push(section, val);
@@ -73,7 +79,7 @@ public class Flood {
     private int[] getOrCreateQueue(long pair, int layer) {
         int[][] arrs = chunkQueues.get(pair);
         if (arrs == null) {
-            chunkQueues.put(pair, arrs = new int[16][]);
+            chunkQueues.put(pair, arrs = new int[sectionCount][]);
         }
         int[] section = arrs[layer];
         if (section == null) {
@@ -154,7 +160,7 @@ public class Flood {
                 if (visit == null || queue == null) {
                     long pair = MathMan.pairInt(this.chunkX + nextX, this.chunkZ + nextZ);
                     int layer = this.chunkYLayer + nextY;
-                    if (layer < 0 || layer > 15) {
+                    if (layer < minSectionIndex || layer > maxSectionIndex) {
                         continue;
                     }
                     queues[sectionIndex] = queue = getOrCreateQueue(pair, layer);

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/SingleThreadQueueExtent.java

@@ -52,6 +52,10 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
     // Chunks currently being queued / worked on
     private final Long2ObjectLinkedOpenHashMap<IQueueChunk> chunks = new Long2ObjectLinkedOpenHashMap<>();
 
+    private World world = null;
+    private int minY = 0;
+    private int maxY = 255;
+
     private IChunkCache<IChunkGet> cacheGet;
     private IChunkCache<IChunkSet> cacheSet;
     private boolean initialized;
@@ -68,7 +72,15 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
 
     private final ReentrantLock getChunkLock = new ReentrantLock();
 
-    private World world = null;
+    public SingleThreadQueueExtent() {}
+
+    /**
+     * New instance given inclusive world height bounds.
+     */
+    public SingleThreadQueueExtent(int minY, int maxY) {
+        this.minY = minY;
+        this.maxY = maxY;
+    }
 
     /**
      * Safety check to ensure that the thread being used matches the one being initialized on. - Can
@@ -111,6 +123,16 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
         return fastmode;
     }
 
+    @Override
+    public int getMinY() {
+        return minY;
+    }
+
+    @Override
+    public int getMaxY() {
+        return maxY;
+    }
+
     /**
      * Resets the queue.
      */
@@ -142,6 +164,8 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
     @Override
     public synchronized void init(Extent extent, IChunkCache<IChunkGet> get, IChunkCache<IChunkSet> set) {
         reset();
+        this.minY = extent.getMinY();
+        this.maxY = extent.getMaxY();
         currentThread = Thread.currentThread();
         if (get == null) {
             get = (x, z) -> {

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/blocks/BitSetBlocks.java

@@ -20,14 +20,21 @@ public class BitSetBlocks implements IChunkSet {
 
     private final MemBlockSet.RowZ row;
     private final BlockState blockState;
+    private final int minSectionIndex;
+    private final int maxSectionIndex;
+    private final int layers;
 
-    public BitSetBlocks(BlockState blockState) {
+    public BitSetBlocks(BlockState blockState, int minSectionIndex, int maxSectionIndex) {
-        this.row = new MemBlockSet.RowZ();
+        this.row = new MemBlockSet.RowZ(minSectionIndex, maxSectionIndex);
         this.blockState = blockState;
+        this.minSectionIndex = minSectionIndex;
+        this.maxSectionIndex = maxSectionIndex;
+        this.layers = maxSectionIndex - minSectionIndex + 1;
     }
 
     @Override
     public boolean hasSection(int layer) {
+        layer -= minSectionIndex;
         return row.rows[layer] != MemBlockSet.NULL_ROW_Y;
     }
 
@@ -39,19 +46,21 @@ public class BitSetBlocks implements IChunkSet {
 
     @Override
     public <T extends BlockStateHolder<T>> boolean setBlock(int x, int y, int z, T holder) {
-        row.set(null, x, y, z);
+        y -= minSectionIndex << 4;
+        row.set(null, x, y, z, minSectionIndex, maxSectionIndex);
         return true;
     }
 
     @Override
     public void setBlocks(int layer, char[] data) {
+        layer -= minSectionIndex;
         row.reset(layer);
         int by = layer << 4;
         for (int y = 0, index = 0; y < 16; y++) {
             for (int z = 0; z < 16; z++) {
                 for (int x = 0; x < 16; x++, index++) {
                     if (data[index] != 0) {
-                        row.set(null, x, by + y, z);
+                        row.set(null, x, by + y, z, minSectionIndex, maxSectionIndex);
                     }
                 }
             }
@@ -114,6 +123,7 @@ public class BitSetBlocks implements IChunkSet {
 
     @Override
     public char[] load(int layer) {
+        layer -= minSectionIndex;
         char[] arr = FaweCache.IMP.SECTION_BITS_TO_CHAR.get();
         MemBlockSet.IRow nullRowY = row.getRow(layer);
         if (nullRowY instanceof MemBlockSet.RowY) {
@@ -189,6 +199,26 @@ public class BitSetBlocks implements IChunkSet {
         return this;
     }
 
+    @Override
+    public boolean hasBiomes(final int layer) {
+        return false;
+    }
+
+    @Override
+    public int getSectionCount() {
+        return layers;
+    }
+
+    @Override
+    public int getMaxSectionIndex() {
+        return minSectionIndex;
+    }
+
+    @Override
+    public int getMinSectionIndex() {
+        return maxSectionIndex;
+    }
+
     @Override
     public boolean trim(boolean aggressive) {
         return false;

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/blocks/CharBlocks.java

@@ -7,7 +7,6 @@ import com.sk89q.worldedit.internal.util.LogManagerCompat;
 import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockTypesCache;
 import org.apache.logging.log4j.Logger;
-import org.jetbrains.annotations.Range;
 
 public abstract class CharBlocks implements IBlocks {
 
@@ -15,30 +14,30 @@ public abstract class CharBlocks implements IBlocks {
 
     protected static final Section FULL = new Section() {
         @Override
-        public final char[] get(CharBlocks blocks, int layer) {
+        public char[] get(CharBlocks blocks, int layer) {
             return blocks.blocks[layer];
         }
 
         // Ignore aggressive switch here.
         @Override
-        public char[] get(CharBlocks blocks, @Range(from = 0, to = 15) int layer, boolean aggressive) {
+        public char[] get(CharBlocks blocks, int layer, boolean aggressive) {
             return blocks.blocks[layer];
         }
 
         @Override
-        public final boolean isFull() {
+        public boolean isFull() {
             return true;
         }
     };
     protected final Section empty = new Section() {
         @Override
-        public final synchronized char[] get(CharBlocks blocks, int layer) {
+        public synchronized char[] get(CharBlocks blocks, int layer) {
             // Defaults to aggressive as it should only be avoided where we know we've reset a chunk during an edit
             return get(blocks, layer, true);
         }
 
         @Override
-        public synchronized char[] get(CharBlocks blocks, @Range(from = 0, to = 15) int layer, boolean aggressive) {
+        public synchronized char[] get(CharBlocks blocks, int layer, boolean aggressive) {
             char[] arr = blocks.blocks[layer];
             if (arr == null) {
                 arr = blocks.blocks[layer] = blocks.update(layer, null, aggressive);
@@ -58,17 +57,26 @@ public abstract class CharBlocks implements IBlocks {
         }
 
         @Override
-        public final boolean isFull() {
+        public boolean isFull() {
             return false;
         }
     };
-    public final char[][] blocks;
+    public char[][] blocks;
-    public final Section[] sections;
+    public Section[] sections;
+    protected int minSectionIndex;
+    protected int maxSectionIndex;
+    protected int sectionCount;
 
-    public CharBlocks() {
+    /**
-        blocks = new char[16][];
+     * New instance given initial min/max section indices. Can be negative.
-        sections = new Section[16];
+     */
-        for (int i = 0; i < 16; i++) {
+    public CharBlocks(int minSectionIndex, int maxSectionIndex) {
+        this.minSectionIndex = minSectionIndex;
+        this.maxSectionIndex = maxSectionIndex;
+        this.sectionCount = maxSectionIndex - minSectionIndex + 1;
+        blocks = new char[sectionCount][];
+        sections = new Section[sectionCount];
+        for (int i = 0; i < sectionCount; i++) {
             sections[i] = empty;
         }
     }
@@ -76,7 +84,7 @@ public abstract class CharBlocks implements IBlocks {
     @Override
     public synchronized boolean trim(boolean aggressive) {
         boolean result = true;
-        for (int i = 0; i < 16; i++) {
+        for (int i = 0; i < sectionCount; i++) {
             if (!sections[i].isFull() && blocks[i] != null) {
                 blocks[i] = null;
             } else {
@@ -99,13 +107,14 @@ public abstract class CharBlocks implements IBlocks {
 
     @Override
     public synchronized IChunkSet reset() {
-        for (int i = 0; i < 16; i++) {
+        for (int i = 0; i < sectionCount; i++) {
             sections[i] = empty;
         }
         return null;
     }
 
-    public synchronized void reset(@Range(from = 0, to = 15) int layer) {
+    public synchronized void reset(int layer) {
+        layer -= minSectionIndex;
         sections[layer] = empty;
     }
 
@@ -121,12 +130,14 @@ public abstract class CharBlocks implements IBlocks {
 
     // Not synchronized as any subsequent methods called from this class will be, or the section shouldn't appear as loaded anyway.
     @Override
-    public boolean hasSection(@Range(from = 0, to = 15) int layer) {
+    public boolean hasSection(int layer) {
-        return sections[layer].isFull();
+        layer -= minSectionIndex;
+        return layer >= 0 && layer < sections.length && sections[layer].isFull();
     }
 
     @Override
-    public char[] load(@Range(from = 0, to = 15) int layer) {
+    public char[] load(int layer) {
+        layer -= minSectionIndex;
         synchronized (sections[layer]) {
             return sections[layer].get(this, layer);
         }
@@ -137,17 +148,17 @@ public abstract class CharBlocks implements IBlocks {
         return BlockTypesCache.states[get(x, y, z)];
     }
 
-    public char get(int x, @Range(from = 0, to = 255) int y, int z) {
+    public char get(int x, int y, int z) {
-        final int layer = y >> 4;
+        int layer = y >> 4;
         final int index = (y & 15) << 8 | z << 4 | x;
-        if (layer >= sections.length || layer < 0) {
+        if (layer > maxSectionIndex || layer < minSectionIndex) {
             return 0;
         }
-        return sections[layer].get(this, layer, index);
+        return get(layer, index);
     }
 
     // Not synchronized as it refers to a synchronized method and includes nothing that requires synchronization
-    public void set(int x, @Range(from = 0, to = 255) int y, int z, char value) {
+    public void set(int x, int y, int z, char value) {
         final int layer = y >> 4;
         final int index = (y & 15) << 8 | z << 4 | x;
         try {
@@ -163,24 +174,26 @@ public abstract class CharBlocks implements IBlocks {
         Section
      */
 
-    public final char get(@Range(from = 0, to = 15) int layer, int index) {
+    public final char get(int layer, int index) {
+        layer -= minSectionIndex;
         return sections[layer].get(this, layer, index);
     }
 
-    public synchronized final void set(@Range(from = 0, to = 15) int layer, int index, char value) throws
+    public synchronized final void set(int layer, int index, char value) throws
             ArrayIndexOutOfBoundsException {
+        layer -= minSectionIndex;
         sections[layer].set(this, layer, index, value);
     }
 
     public abstract static class Section {
 
-        public abstract char[] get(CharBlocks blocks, @Range(from = 0, to = 15) int layer);
+        public abstract char[] get(CharBlocks blocks, int layer);
 
-        public abstract char[] get(CharBlocks blocks, @Range(from = 0, to = 15) int layer, boolean aggressive);
+        public abstract char[] get(CharBlocks blocks, int layer, boolean aggressive);
 
         public abstract boolean isFull();
 
-        public final char get(CharBlocks blocks, @Range(from = 0, to = 15) int layer, int index) {
+        public final char get(CharBlocks blocks, int layer, int index) {
             char[] section = get(blocks, layer);
             if (section == null) {
                 blocks.reset(layer);
@@ -189,7 +202,7 @@ public abstract class CharBlocks implements IBlocks {
             return section[index];
         }
 
-        public final void set(CharBlocks blocks, @Range(from = 0, to = 15) int layer, int index, char value) {
+        public final void set(CharBlocks blocks, int layer, int index, char value) {
             get(blocks, layer)[index] = value;
         }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/blocks/CharGetBlocks.java

@@ -10,6 +10,13 @@ import java.util.Arrays;
 
 public abstract class CharGetBlocks extends CharBlocks implements IChunkGet {
 
+    /**
+     * New instance given the min/max section indices
+     */
+    public CharGetBlocks(final int minSectionIndex, final int maxSectionIndex) {
+        super(minSectionIndex, maxSectionIndex);
+    }
+
     @Override
     public BaseBlock getFullBlock(int x, int y, int z) {
         BlockState state = BlockTypesCache.states[get(x, y, z)];
@@ -18,7 +25,7 @@ public abstract class CharGetBlocks extends CharBlocks implements IChunkGet {
 
     @Override
     public boolean trim(boolean aggressive) {
-        for (int i = 0; i < 16; i++) {
+        for (int i = 0; i < sectionCount; i++) {
             sections[i] = empty;
             blocks[i] = null;
         }
@@ -36,6 +43,7 @@ public abstract class CharGetBlocks extends CharBlocks implements IChunkGet {
 
     @Override
     public synchronized boolean trim(boolean aggressive, int layer) {
+        layer -= minSectionIndex;
         sections[layer] = empty;
         blocks[layer] = null;
         return true;
@@ -47,4 +55,9 @@ public abstract class CharGetBlocks extends CharBlocks implements IChunkGet {
         return null;
     }
 
+    @Override
+    public int getSectionCount() {
+        return sectionCount;
+    }
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/blocks/CharSetBlocks.java

@@ -11,7 +11,6 @@ import com.sk89q.worldedit.WorldEditException;
 import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
-import org.jetbrains.annotations.Range;
 
 import java.util.Arrays;
 import java.util.Collections;
@@ -45,6 +44,8 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
     private int bitMask = -1;
 
     private CharSetBlocks() {
+        // Expand as we go
+        super(0, 15);
     }
 
     @Override
@@ -59,9 +60,10 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public BiomeType getBiomeType(int x, int y, int z) {
-        if (biomes == null) {
+        if (biomes == null || (y >> 4) < minSectionIndex || (y >> 4) > maxSectionIndex) {
             return null;
         }
+        y -= minSectionIndex << 4;
         return biomes[(y >> 2) << 4 | (z >> 2) << 2 | x >> 2];
     }
 
@@ -92,15 +94,18 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public boolean setBiome(int x, int y, int z, BiomeType biome) {
+        updateSectionIndexRange(y >> 4);
+        y -= minSectionIndex << 4;
         if (biomes == null) {
-            biomes = new BiomeType[1024];
+            biomes = new BiomeType[64 * sectionCount];
         }
         biomes[(y >> 2) << 4 | (z >> 2) << 2 | x >> 2] = biome;
         return true;
     }
 
     @Override
-    public <T extends BlockStateHolder<T>> boolean setBlock(int x, @Range(from = 0, to = 255) int y, int z, T holder) {
+    public <T extends BlockStateHolder<T>> boolean setBlock(int x, int y, int z, T holder) {
+        updateSectionIndexRange(y >> 4);
         set(x, y, z, holder.getOrdinalChar());
         holder.applyTileEntity(this, x, y, z);
         return true;
@@ -108,6 +113,8 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public void setBlocks(int layer, char[] data) {
+        updateSectionIndexRange(layer);
+        layer -= minSectionIndex;
         this.blocks[layer] = data;
         this.sections[layer] = data == null ? empty : FULL;
     }
@@ -123,38 +130,41 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
         if (tiles == null) {
             tiles = new BlockVector3ChunkMap<>();
         }
+        updateSectionIndexRange(y >> 4);
         tiles.put(x, y, z, tile);
         return true;
     }
 
     @Override
     public void setBlockLight(int x, int y, int z, int value) {
+        updateSectionIndexRange(y >> 4);
         if (light == null) {
-            light = new char[16][];
+            light = new char[sectionCount][];
         }
-        final int layer = y >> 4;
+        final int layer = (y >> 4) - minSectionIndex;
         if (light[layer] == null) {
             char[] c = new char[4096];
             Arrays.fill(c, (char) 16);
             light[layer] = c;
         }
         final int index = (y & 15) << 8 | (z & 15) << 4 | (x & 15);
-        light[y >> 4][index] = (char) value;
+        light[layer][index] = (char) value;
     }
 
     @Override
     public void setSkyLight(int x, int y, int z, int value) {
+        updateSectionIndexRange(y >> 4);
         if (skyLight == null) {
-            skyLight = new char[16][];
+            skyLight = new char[sectionCount][];
         }
-        final int layer = y >> 4;
+        final int layer = (y >> 4) - minSectionIndex;
         if (skyLight[layer] == null) {
             char[] c = new char[4096];
             Arrays.fill(c, (char) 16);
             skyLight[layer] = c;
         }
         final int index = (y & 15) << 8 | (z & 15) << 4 | (x & 15);
-        skyLight[y >> 4][index] = (char) value;
+        skyLight[layer][index] = (char) value;
     }
 
     @Override
@@ -167,17 +177,21 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public void setLightLayer(int layer, char[] toSet) {
+        updateSectionIndexRange(layer);
         if (light == null) {
-            light = new char[16][];
+            light = new char[sectionCount][];
         }
+        layer -= minSectionIndex;
         light[layer] = toSet;
     }
 
     @Override
     public void setSkyLightLayer(int layer, char[] toSet) {
+        updateSectionIndexRange(layer);
         if (skyLight == null) {
-            skyLight = new char[16][];
+            skyLight = new char[sectionCount][];
         }
+        layer -= minSectionIndex;
         skyLight[layer] = toSet;
     }
 
@@ -193,8 +207,10 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public void removeSectionLighting(int layer, boolean sky) {
+        updateSectionIndexRange(layer);
+        layer -= minSectionIndex;
         if (light == null) {
-            light = new char[16][];
+            light = new char[sectionCount][];
         }
         if (light[layer] == null) {
             light[layer] = new char[4096];
@@ -202,7 +218,7 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
         Arrays.fill(light[layer], (char) 0);
         if (sky) {
             if (skyLight == null) {
-                skyLight = new char[16][];
+                skyLight = new char[sectionCount][];
             }
             if (skyLight[layer] == null) {
                 skyLight[layer] = new char[4096];
@@ -213,14 +229,16 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
 
     @Override
     public void setFullBright(int layer) {
+        updateSectionIndexRange(layer);
+        layer -= minSectionIndex;
         if (light == null) {
-            light = new char[16][];
+            light = new char[sectionCount][];
         }
         if (light[layer] == null) {
             light[layer] = new char[4096];
         }
         if (skyLight == null) {
-            skyLight = new char[16][];
+            skyLight = new char[sectionCount][];
         }
         if (skyLight[layer] == null) {
             skyLight[layer] = new char[4096];
@@ -275,7 +293,7 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
         if (biomes != null || light != null || skyLight != null) {
             return false;
         }
-        return IntStream.range(0, 16).noneMatch(this::hasSection);
+        return IntStream.range(minSectionIndex, maxSectionIndex + 1).noneMatch(this::hasSection);
     }
 
     @Override
@@ -288,4 +306,98 @@ public class CharSetBlocks extends CharBlocks implements IChunkSet {
         return null;
     }
 
+    @Override
+    public boolean hasBiomes(int layer) {
+        layer -= minSectionIndex;
+        if (layer < 0 || layer >= sections.length) {
+            return false;
+        }
+        return biomes != null;
+    }
+
+    @Override
+    public char[] load(final int layer) {
+        updateSectionIndexRange(layer);
+        return super.load(layer);
+    }
+
+    @Override
+    public int getSectionCount() {
+        return sectionCount;
+    }
+
+    @Override
+    public int getMaxSectionIndex() {
+        return maxSectionIndex;
+    }
+
+    @Override
+    public int getMinSectionIndex() {
+        return minSectionIndex;
+    }
+
+    // Checks and updates the various section arrays against the new layer index
+    private void updateSectionIndexRange(int layer) {
+        if (layer >= minSectionIndex && layer <= maxSectionIndex) {
+            return;
+        }
+        if (layer < minSectionIndex) {
+            int diff = minSectionIndex - layer;
+            sectionCount += diff;
+            char[][] tmpBlocks = new char[sectionCount][];
+            Section[] tmpSections = new Section[sectionCount];
+            System.arraycopy(blocks, 0, tmpBlocks, diff, blocks.length);
+            System.arraycopy(sections, 0, tmpSections, diff, sections.length);
+            for (int i = 0; i < diff; i++) {
+                tmpSections[i] = empty;
+            }
+            blocks = tmpBlocks;
+            sections = tmpSections;
+            minSectionIndex = layer;
+            if (biomes != null) {
+                BiomeType[] tmpBiomes = new BiomeType[sectionCount * 64];
+                System.arraycopy(biomes, 0, tmpBiomes, 64*diff, biomes.length);
+                biomes = tmpBiomes;
+            }
+            if (light != null) {
+                char[][] tmplight = new char[sectionCount][];
+                System.arraycopy(light, 0, tmplight, diff, light.length);
+                light = tmplight;
+            }
+            if (skyLight != null) {
+                char[][] tmplight = new char[sectionCount][];
+                System.arraycopy(skyLight, 0, tmplight, diff, skyLight.length);
+                skyLight = tmplight;
+            }
+        } else {
+            int diff = layer - maxSectionIndex;
+            sectionCount += diff;
+            char[][] tmpBlocks = new char[sectionCount][];
+            Section[] tmpSections = new Section[sectionCount];
+            System.arraycopy(blocks, 0, tmpBlocks, 0, blocks.length);
+            System.arraycopy(sections, 0, tmpSections, 0, sections.length);
+            for (int i = sectionCount - diff; i < sectionCount; i++) {
+                tmpSections[i] = empty;
+            }
+            blocks = tmpBlocks;
+            sections = tmpSections;
+            maxSectionIndex = layer;
+            if (biomes != null) {
+                BiomeType[] tmpBiomes = new BiomeType[sectionCount * 64];
+                System.arraycopy(biomes, 0, tmpBiomes, 0, biomes.length);
+                biomes = tmpBiomes;
+            }
+            if (light != null) {
+                char[][] tmplight = new char[sectionCount][];
+                System.arraycopy(light, 0, tmplight, 0, light.length);
+                light = tmplight;
+            }
+            if (skyLight != null) {
+                char[][] tmplight = new char[sectionCount][];
+                System.arraycopy(skyLight, 0, tmplight, 0, skyLight.length);
+                skyLight = tmplight;
+            }
+        }
+    }
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/blocks/NullChunkGet.java

@@ -78,17 +78,37 @@ public final class NullChunkGet implements IChunkGet {
     }
 
     @Override
-    public void setLightingToGet(char[][] lighting) {
+    public void setLightingToGet(char[][] lighting, int startSectionIndex, int endSectionIndex) {
     }
 
     @Override
-    public void setSkyLightingToGet(char[][] lighting) {
+    public void setSkyLightingToGet(char[][] lighting, int minSectionIndex, int maxSectionIndex) {
     }
 
     @Override
     public void setHeightmapToGet(HeightMapType type, int[] data) {
     }
 
+    @Override
+    public int getMaxY() {
+        return 0;
+    }
+
+    @Override
+    public int getMinY() {
+        return 0;
+    }
+
+    @Override
+    public int getMaxSectionIndex() {
+        return 0;
+    }
+
+    @Override
+    public int getMinSectionIndex() {
+        return 0;
+    }
+
     public boolean trim(boolean aggressive) {
         return true;
     }
@@ -129,6 +149,11 @@ public final class NullChunkGet implements IChunkGet {
         return null;
     }
 
+    @Override
+    public int getSectionCount() {
+        return 0;
+    }
+
     private NullChunkGet() {
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/chunk/ChunkHolder.java

@@ -19,7 +19,6 @@ import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
-import org.jetbrains.annotations.Range;
 
 import javax.annotation.Nullable;
 import java.util.Map;
@@ -140,6 +139,12 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         return bitMask;
     }
 
+    @Override
+    public boolean hasBiomes(final int layer) {
+        // No need to go through delegate. hasBiomes is SET only.
+        return getOrCreateSet().hasBiomes(layer);
+    }
+
     public boolean isInit() {
         return isInit;
     }
@@ -160,12 +165,12 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
     }
 
     @Override
-    public void setLightingToGet(char[][] lighting) {
+    public void setLightingToGet(char[][] lighting, int minSectionIndex, int maxSectionIndex) {
         delegate.setLightingToGet(this, lighting);
     }
 
     @Override
-    public void setSkyLightingToGet(char[][] lighting) {
+    public void setSkyLightingToGet(char[][] lighting, int minSectionIndex, int maxSectionIndex) {
         delegate.setSkyLightingToGet(this, lighting);
     }
 
@@ -174,8 +179,28 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         delegate.setHeightmapToGet(this, type, data);
     }
 
-    public void flushLightToGet(boolean heightmaps) {
+    @Override
-        delegate.flushLightToGet(this, heightmaps);
+    public int getMaxY() {
+        return getOrCreateGet().getMaxY();
+    }
+
+    @Override
+    public int getMinY() {
+        return getOrCreateGet().getMinY();
+    }
+
+    @Override
+    public int getMaxSectionIndex() {
+        return getOrCreateGet().getMaxSectionIndex();
+    }
+
+    @Override
+    public int getMinSectionIndex() {
+        return getOrCreateGet().getMinSectionIndex();
+    }
+
+    public void flushLightToGet() {
+        delegate.flushLightToGet(this);
     }
 
     private static final IBlockDelegate BOTH = new IBlockDelegate() {
@@ -260,6 +285,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         public int getSkyLight(ChunkHolder chunk, int x, int y, int z) {
             if (chunk.chunkSet.getSkyLight() != null) {
                 int layer = y >> 4;
+                layer -= chunk.chunkSet.getMinSectionIndex();
                 if (chunk.chunkSet.getSkyLight()[layer] != null) {
                     int setLightValue = chunk.chunkSet.getSkyLight()[layer][(y & 15) << 8 | (z & 15) << 4 | (x & 15)];
                     if (setLightValue < 16) {
@@ -274,6 +300,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         public int getEmittedLight(ChunkHolder chunk, int x, int y, int z) {
             if (chunk.chunkSet.getLight() != null) {
                 int layer = y >> 4;
+                layer -= chunk.chunkSet.getMinSectionIndex();
                 if (chunk.chunkSet.getLight()[layer] != null) {
                     int setLightValue = chunk.chunkSet.getLight()[layer][(y & 15) << 8 | (z & 15) << 4 | (x & 15)];
                     if (setLightValue < 16) {
@@ -300,19 +327,21 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         }
 
         @Override
-        public void flushLightToGet(ChunkHolder chunk, boolean heightmaps) {
+        public void flushLightToGet(ChunkHolder chunk) {
-            chunk.chunkExisting.setLightingToGet(chunk.chunkSet.getLight());
+            chunk.chunkExisting.setLightingToGet(chunk.chunkSet.getLight(), chunk.chunkSet.getMinSectionIndex(),
-            chunk.chunkExisting.setSkyLightingToGet(chunk.chunkSet.getSkyLight());
+                    chunk.chunkSet.getMaxSectionIndex());
+            chunk.chunkExisting.setSkyLightingToGet(chunk.chunkSet.getSkyLight(), chunk.chunkSet.getMinSectionIndex(),
+                    chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
         public void setLightingToGet(ChunkHolder chunk, char[][] lighting) {
-            chunk.chunkExisting.setLightingToGet(lighting);
+            chunk.chunkExisting.setLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
         public void setSkyLightingToGet(ChunkHolder chunk, char[][] lighting) {
-            chunk.chunkExisting.setSkyLightingToGet(lighting);
+            chunk.chunkExisting.setSkyLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -447,18 +476,18 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         }
 
         @Override
-        public void flushLightToGet(ChunkHolder chunk, boolean heightmaps) {
+        public void flushLightToGet(ChunkHolder chunk) {
             // Do nothing as no lighting to flush to GET
         }
 
         @Override
         public void setLightingToGet(ChunkHolder chunk, char[][] lighting) {
-            chunk.chunkExisting.setLightingToGet(lighting);
+            chunk.chunkExisting.setLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
         public void setSkyLightingToGet(ChunkHolder chunk, char[][] lighting) {
-            chunk.chunkExisting.setSkyLightingToGet(lighting);
+            chunk.chunkExisting.setSkyLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -493,7 +522,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         public <B extends BlockStateHolder<B>> boolean setBlock(
                 ChunkHolder chunk,
                 int x,
-                @Range(from = 0, to = 255) int y,
+                int y,
                 int z,
                 B block
         ) {
@@ -568,6 +597,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         public int getSkyLight(ChunkHolder chunk, int x, int y, int z) {
             if (chunk.chunkSet.getSkyLight() != null) {
                 int layer = y >> 4;
+                layer -= chunk.chunkSet.getMinSectionIndex();
                 if (chunk.chunkSet.getSkyLight()[layer] != null) {
                     int setLightValue = chunk.chunkSet.getSkyLight()[layer][(y & 15) << 8 | (z & 15) << 4 | (x & 15)];
                     if (setLightValue < 16) {
@@ -585,6 +615,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         public int getEmittedLight(ChunkHolder chunk, int x, int y, int z) {
             if (chunk.chunkSet.getLight() != null) {
                 int layer = y >> 4;
+                layer -= chunk.chunkSet.getMinSectionIndex();
                 if (chunk.chunkSet.getLight()[layer] != null) {
                     int setLightValue = chunk.chunkSet.getLight()[layer][(y & 15) << 8 | (z & 15) << 4 | (x & 15)];
                     if (setLightValue < 16) {
@@ -623,12 +654,11 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         }
 
         @Override
-        public void flushLightToGet(ChunkHolder chunk, boolean heightmaps) {
+        public void flushLightToGet(ChunkHolder chunk) {
             chunk.getOrCreateGet();
             chunk.delegate = BOTH;
             chunk.chunkExisting.trim(false);
-            chunk.chunkExisting.setLightingToGet(chunk.chunkSet.getLight());
+            chunk.flushLightToGet();
-            chunk.chunkExisting.setSkyLightingToGet(chunk.chunkSet.getSkyLight());
         }
 
         @Override
@@ -636,7 +666,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
             chunk.getOrCreateGet();
             chunk.delegate = BOTH;
             chunk.chunkExisting.trim(false);
-            chunk.chunkExisting.setLightingToGet(lighting);
+            chunk.setLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -644,7 +674,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
             chunk.getOrCreateGet();
             chunk.delegate = BOTH;
             chunk.chunkExisting.trim(false);
-            chunk.chunkExisting.setSkyLightingToGet(lighting);
+            chunk.setSkyLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -652,7 +682,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
             chunk.getOrCreateGet();
             chunk.delegate = BOTH;
             chunk.chunkExisting.trim(false);
-            chunk.chunkExisting.setHeightmapToGet(type, data);
+            chunk.setHeightmapToGet(type, data);
         }
     };
 
@@ -804,7 +834,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         }
 
         @Override
-        public void flushLightToGet(ChunkHolder chunk, boolean heightmaps) {
+        public void flushLightToGet(ChunkHolder chunk) {
             // Do nothing as no light to flush
         }
 
@@ -813,7 +843,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
             chunk.getOrCreateGet();
             chunk.delegate = GET;
             chunk.chunkExisting.trim(false);
-            chunk.setLightingToGet(lighting);
+            chunk.setLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -821,7 +851,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
             chunk.getOrCreateGet();
             chunk.delegate = GET;
             chunk.chunkExisting.trim(false);
-            chunk.setSkyLightingToGet(lighting);
+            chunk.setSkyLightingToGet(lighting, chunk.chunkSet.getMinSectionIndex(), chunk.chunkSet.getMaxSectionIndex());
         }
 
         @Override
@@ -889,6 +919,11 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         return this.trim(aggressive);
     }
 
+    @Override
+    public int getSectionCount() {
+        return getOrCreateGet().getSectionCount();
+    }
+
     @Override
     public boolean isEmpty() {
         return chunkSet == null || chunkSet.isEmpty();
@@ -1117,7 +1152,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
 
         int[] getHeightMap(ChunkHolder chunk, HeightMapType type);
 
-        void flushLightToGet(ChunkHolder chunk, boolean heightmaps);
+        void flushLightToGet(ChunkHolder chunk);
 
         void setLightingToGet(ChunkHolder chunk, char[][] lighting);
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/chunk/NullChunk.java

@@ -82,6 +82,11 @@ public final class NullChunk implements IQueueChunk {
         return new char[0][];
     }
 
+    @Override
+    public boolean hasBiomes(final int layer) {
+        return false;
+    }
+
     @Nonnull
     public int[] getHeightMap(@Nullable HeightMapType type) {
         return new int[256];
@@ -182,17 +187,37 @@ public final class NullChunk implements IQueueChunk {
     }
 
     @Override
-    public void setLightingToGet(char[][] lighting) {
+    public void setLightingToGet(char[][] lighting, int minSectionIndex, int maxSectionIndex) {
     }
 
     @Override
-    public void setSkyLightingToGet(char[][] lighting) {
+    public void setSkyLightingToGet(char[][] lighting, int minSectionIndex, int maxSectionIndex) {
     }
 
     @Override
     public void setHeightmapToGet(HeightMapType type, int[] data) {
     }
 
+    @Override
+    public int getMaxY() {
+        return 0;
+    }
+
+    @Override
+    public int getMinY() {
+        return 0;
+    }
+
+    @Override
+    public int getMaxSectionIndex() {
+        return 0;
+    }
+
+    @Override
+    public int getMinSectionIndex() {
+        return 0;
+    }
+
     @Nullable
     public <T extends Future<T>> T call(@Nullable IChunkSet set, @Nullable Runnable finalize) {
         return null;
@@ -206,6 +231,11 @@ public final class NullChunk implements IQueueChunk {
         return true;
     }
 
+    @Override
+    public int getSectionCount() {
+        return 0;
+    }
+
     private NullChunk() {
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/regions/FuzzyRegion.java

@@ -51,7 +51,7 @@ public class FuzzyRegion extends AbstractRegion {
         RecursiveVisitor search = new RecursiveVisitor(mask, p -> {
             setMinMax(p.getBlockX(), p.getBlockY(), p.getBlockZ());
             return true;
-        }, 256);
+        }, 256, extent.getMinY(), extent.getMaxY());
         search.setVisited(set);
         search.visit(BlockVector3.at(x, y, z));
         Operations.completeBlindly(search);

worldedit-core/src/main/java/com/fastasyncworldedit/core/regions/RegionWrapper.java

@@ -7,6 +7,8 @@ import com.sk89q.worldedit.regions.CuboidRegion;
 public class RegionWrapper extends CuboidRegion {
 
     private static final RegionWrapper GLOBAL = new RegionWrapper(
+            Integer.MIN_VALUE,
+            Integer.MAX_VALUE,
             Integer.MIN_VALUE,
             Integer.MAX_VALUE,
             Integer.MIN_VALUE,
@@ -20,16 +22,16 @@ public class RegionWrapper extends CuboidRegion {
     public int minZ;
     public int maxZ;
 
-    public static RegionWrapper GLOBAL() {
+    /**
-        return GLOBAL;
+     * @deprecated use {@link RegionWrapper#RegionWrapper(int, int, int, int, int, int)}
-    }
+     */
-
+    @Deprecated
     public RegionWrapper(final int minX, final int maxX, final int minZ, final int maxZ) {
         this(minX, maxX, 0, 255, minZ, maxZ);
     }
 
     public RegionWrapper(final int minX, final int maxX, final int minY, final int maxY, final int minZ, final int maxZ) {
-        this(BlockVector3.at(minX, 0, minZ), BlockVector3.at(maxX, 255, maxZ));
+        this(BlockVector3.at(minX, minY, minZ), BlockVector3.at(maxX, maxY, maxZ));
     }
 
     public RegionWrapper(final BlockVector3 pos1, final BlockVector3 pos2) {
@@ -42,6 +44,10 @@ public class RegionWrapper extends CuboidRegion {
         this.maxY = Math.max(pos1.getBlockY(), pos2.getBlockY());
     }
 
+    public static RegionWrapper GLOBAL() {
+        return GLOBAL;
+    }
+
     @Override
     protected void recalculate() {
         super.recalculate();
@@ -134,7 +140,8 @@ public class RegionWrapper extends CuboidRegion {
 
     @Override
     public boolean isGlobal() {
-        return minX == Integer.MIN_VALUE && minZ == Integer.MIN_VALUE && maxX == Integer.MAX_VALUE && maxZ == Integer.MAX_VALUE && minY <= 0 && maxY >= 255;
+        return minX == Integer.MIN_VALUE && minY == Integer.MIN_VALUE && minZ == Integer.MIN_VALUE
+                && maxX == Integer.MAX_VALUE && maxY == Integer.MAX_VALUE && maxZ == Integer.MAX_VALUE;
     }
 
     public boolean contains(RegionWrapper current) {

worldedit-core/src/main/java/com/fastasyncworldedit/core/util/MathMan.java

@@ -152,52 +152,65 @@ public class MathMan {
     }
 
     public static long tripleWorldCoord(int x, int y, int z) {
-        return y + (((long) x & 0x3FFFFFF) << 8) + (((long) z & 0x3FFFFFF) << 34);
+        return ((y + 256) & 0xffff) + (((long) x & 0xffffff) << 16) + (((long) z & 0xffffff) << 40);
     }
 
     public static long untripleWorldCoordX(long triple) {
-        return (((triple >> 8) & 0x3FFFFFF) << 38) >> 38;
+        return (((triple >> 16) & 0xffffff) << 38) >> 38;
     }
 
     public static long untripleWorldCoordY(long triple) {
-        return triple & 0xFF;
+        return (triple & 0xffff) - 256;
     }
 
     public static long untripleWorldCoordZ(long triple) {
-        return (((triple >> 34) & 0x3FFFFFF) << 38) >> 38;
+        return (((triple >> 40) & 0xffffff) << 38) >> 38;
     }
 
-    public static short tripleBlockCoord(int x, int y, int z) {
+    public static int tripleBlockCoord(int x, int y, int z) {
-        return (short) ((x & 15) << 12 | (z & 15) << 8 | y);
+        // account for the fact y can be negative now. Assume it won't be less than -256
+        y += 256;
+        return ((x & 15) << 16 | (z & 15) << 12 | y);
     }
 
     public static char tripleBlockCoordChar(int x, int y, int z) {
-        return (char) ((x & 15) << 12 | (z & 15) << 8 | y);
+        return (char) ((x & 15) << 16 | (z & 15) << 12 | y);
     }
 
     public static int untripleBlockCoordX(int triple) {
-        return (triple >> 12) & 0xF;
+        return (triple >> 16) & 0xF;
     }
 
     public static int untripleBlockCoordY(int triple) {
-        return (triple & 0xFF);
+        return (triple & 0x1ff) - 256;
     }
 
     public static int untripleBlockCoordZ(int triple) {
-        return (triple >> 8) & 0xF;
+        return (triple >> 12) & 0xF;
     }
 
+    /**
+     * Obtain an integer representation of 3 ints, x, y and z. y is represented by the right-most 9 bits and can
+     * be within the range -256 to 255 (inclusive). x and z are represented by 11 bits each and can be within the range
+     * -1024 to 1023 (inclusive).
+     *
+     * @param x x value
+     * @param y y value
+     * @param z z value
+     * @return integer representation of x y z
+     */
     public static int tripleSearchCoords(int x, int y, int z) {
-        byte b1 = (byte) y;
+        if (x > 1023 || x < -1024 || y > 255 || y < -256 || z > 1023 || z < -1024) {
-        byte b3 = (byte) (x);
+            throw new IndexOutOfBoundsException(String.format("Check range on x=%s, y=%s and z=%s!", x, y, z));
-        byte b4 = (byte) (z);
+        }
-        int x16 = (x >> 8) & 0x7;
+        int b1 = Math.abs(y) & 0xff;
-        int z16 = (z >> 8) & 0x7;
+        int b3 = x & 0xff;
-        byte b2 = MathMan.pair8(x16, z16);
+        int b4 = z & 0xff;
-        return ((b1 & 0xFF)
+        int x16 = (((x >> 8) & 0x3) | (x < 0 ? 0x4 : 0x00));
-                + ((b2 & 0x7F) << 8)
+        int z16 = (((z >> 8) & 0x3) | (z < 0 ? 0x4 : 0x00));
-                + ((b3 & 0xFF) << 15)
+        int y16 = (y < 0 ? 0x1 : 0x00);
-                + ((b4 & 0xFF) << 23));
+        int b2 = ((x16 + (z16 << 3) + (y16 << 6)));
+        return (((b1) | (b2 << 8)) | (b3 << 15)) | (b4 << 23);
     }
 
     public static int pairSearchCoords(int x, int y) {

worldedit-core/src/main/java/com/fastasyncworldedit/core/util/collection/MemBlockSet.java

@@ -28,17 +28,17 @@ public final class MemBlockSet extends BlockSet {
     public static final IRow NULL_ROW_Y = new NullRowY();
     public final IRow[] rows;
     public final MutableBlockVector3 mutable;
+    private final int minSectionIndex;
+    private final int maxSectionIndex;
 
-    public MemBlockSet() {
+    public MemBlockSet(int size, int offsetX, int offsetZ, int minSectionIndex, int maxSectionIndex) {
-        this(16, 0, 0);
-    }
-
-    public MemBlockSet(int size, int offsetX, int offsetZ) {
         super(offsetX, offsetZ);
         this.rows = new IRow[size];
         for (int i = 0; i < size; i++) {
             rows[i] = NULL_ROW_X;
         }
+        this.minSectionIndex = minSectionIndex;
+        this.maxSectionIndex = maxSectionIndex;
         this.mutable = new MutableBlockVector3();
     }
 
@@ -53,14 +53,14 @@ public final class MemBlockSet extends BlockSet {
     public boolean add(int x, int y, int z) {
         x -= getBlockOffsetX();
         z -= getBlockOffsetZ();
-        return rows[x >> 4].add(this.rows, x, y, z - getBlockOffsetZ());
+        return rows[x >> 4].add(this.rows, x, y, z - getBlockOffsetZ(), minSectionIndex, maxSectionIndex);
     }
 
     @Override
     public void set(int x, int y, int z) {
         x -= getBlockOffsetX();
         z -= getBlockOffsetZ();
-        rows[x >> 4].set(this.rows, x, y, z - getBlockOffsetZ());
+        rows[x >> 4].set(this.rows, x, y, z - getBlockOffsetZ(), minSectionIndex, maxSectionIndex);
     }
 
     @Override
@@ -88,11 +88,11 @@ public final class MemBlockSet extends BlockSet {
 
     @Override
     public Set<BlockVector2> getChunks() {
-        return new AbstractSet<BlockVector2>() {
+        return new AbstractSet<>() {
             @Nonnull
             @Override
             public Iterator<BlockVector2> iterator() {
-                return new Iterator<BlockVector2>() {
+                return new Iterator<>() {
                     private final MutableBlockVector2 mutable = new MutableBlockVector2();
                     private boolean hasNext;
                     private int X;
@@ -181,10 +181,10 @@ public final class MemBlockSet extends BlockSet {
     }
 
     public Set<BlockVector3> getChunkCubes() {
-        return new AbstractSet<BlockVector3>() {
+        return new AbstractSet<>() {
             @Override
             public Iterator<BlockVector3> iterator() {
-                return new Iterator<BlockVector3>() {
+                return new Iterator<>() {
                     private final MutableBlockVector3 mutable = new MutableBlockVector3();
                     private boolean hasNext;
                     private int X;
@@ -234,7 +234,7 @@ public final class MemBlockSet extends BlockSet {
                     @Override
                     public BlockVector3 next() {
                         mutable.setComponents(
-                                setX + getBlockOffsetX(), setY, setZ + getBlockOffsetX());
+                                setX + getBlockOffsetX(), setY - (minSectionIndex << 4), setZ + getBlockOffsetX());
                         init();
                         return mutable;
                     }
@@ -282,7 +282,7 @@ public final class MemBlockSet extends BlockSet {
                     if (rowx instanceof RowX) {
                         IRow rowz = ((RowX) rowx).rows[other.getZ()];
                         if (rowz instanceof RowZ) {
-                            return ((RowZ) rowz).rows[other.getY() - getChunkOffsetZ()] instanceof RowY;
+                            return ((RowZ) rowz).rows[other.getY() - (minSectionIndex << 4) - getChunkOffsetZ()] instanceof RowY;
                         }
                     }
                 }
@@ -293,7 +293,7 @@ public final class MemBlockSet extends BlockSet {
 
     @Override
     public int getMinimumY() {
-        int maxY = 15;
+        int maxY = maxSectionIndex;
         int maxy = 16;
         int by = Integer.MAX_VALUE;
         for (IRow nullRowX : rows) {
@@ -357,7 +357,7 @@ public final class MemBlockSet extends BlockSet {
                 }
                 RowZ rowz = (RowZ) nullRowZ;
                 outer:
-                for (int Y = 15; Y >= maxY; Y--) {
+                for (int Y = maxSectionIndex; Y >= maxY; Y--) {
                     IRow nullRowY = rowz.rows[Y];
                     if (!(nullRowY instanceof RowY)) {
                         continue;
@@ -376,8 +376,8 @@ public final class MemBlockSet extends BlockSet {
                                     maxy = y + 1;
                                 }
                                 by = (Y << 4) + y;
-                                if (by == FaweCache.IMP.WORLD_MAX_Y) {
+                                if (by == (maxSectionIndex << 4) + 15) {
-                                    return FaweCache.IMP.WORLD_MAX_Y;
+                                    return (maxSectionIndex << 4) + 15;
                                 }
                                 break outer;
                             }
@@ -582,7 +582,7 @@ public final class MemBlockSet extends BlockSet {
                     if (!(nullRowY instanceof RowY)) {
                         continue;
                     }
-                    int by = Y << 4;
+                    int by = ((Y - minSectionIndex) << 4);
                     RowY rowY = (RowY) nullRowY;
                     for (int y = 0, i = 0; y < 16; y++) {
                         for (int z = 0; z < 16; z += 4, i++) {
@@ -615,7 +615,7 @@ public final class MemBlockSet extends BlockSet {
 
     @Override
     public Iterator<BlockVector3> iterator() {
-        return new Iterator<BlockVector3>() {
+        return new Iterator<>() {
             private int bx;
             private int by;
             private int bz;
@@ -817,10 +817,10 @@ public final class MemBlockSet extends BlockSet {
             return false;
         }
 
-        void set(IRow[] rows, int x, int y, int z);
+        void set(IRow[] rows, int x, int y, int z, int minSectionIndex, int maxSectionIndex);
 
-        default boolean add(IRow[] rows, int x, int y, int z) {
+        default boolean add(IRow[] rows, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            set(rows, x, y, z);
+            set(rows, x, y, z, minSectionIndex, maxSectionIndex);
             return true;
         }
 
@@ -837,10 +837,10 @@ public final class MemBlockSet extends BlockSet {
     public static final class NullRowX implements IRow {
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
             IRow row = new RowX(parent.length);
             parent[x >> 4] = row;
-            row.set(parent, x, y, z);
+            row.set(parent, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
     }
@@ -848,10 +848,10 @@ public final class MemBlockSet extends BlockSet {
     public static final class NullRowZ implements IRow {
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            IRow row = new RowZ();
+            IRow row = new RowZ(minSectionIndex, maxSectionIndex);
             parent[z >> 4] = row;
-            row.set(parent, x, y, z);
+            row.set(parent, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
     }
@@ -859,10 +859,10 @@ public final class MemBlockSet extends BlockSet {
     public static final class NullRowY implements IRow {
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
             IRow row = new RowY();
             parent[y >> 4] = row;
-            row.set(parent, x, y, z);
+            row.set(parent, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
     }
@@ -884,13 +884,13 @@ public final class MemBlockSet extends BlockSet {
         }
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            this.rows[z >> 4].set(this.rows, x, y, z);
+            this.rows[z >> 4].set(this.rows, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
         @Override
-        public boolean add(IRow[] parent, int x, int y, int z) {
+        public boolean add(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            return this.rows[z >> 4].add(this.rows, x, y, z);
+            return this.rows[z >> 4].add(this.rows, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
         @Override
@@ -909,8 +909,8 @@ public final class MemBlockSet extends BlockSet {
 
         public final IRow[] rows;
 
-        public RowZ() {
+        public RowZ(int minSectionIndex, int maxSectionIndex) {
-            this.rows = new IRow[FaweCache.IMP.CHUNK_LAYERS];
+            this.rows = new IRow[maxSectionIndex - minSectionIndex + 1];
             reset();
         }
 
@@ -924,18 +924,19 @@ public final class MemBlockSet extends BlockSet {
         }
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            this.rows[y >> 4].set(this.rows, x, y, z);
+            this.rows[y >> 4].set(this.rows, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
         @Override
-        public boolean add(IRow[] parent, int x, int y, int z) {
+        public boolean add(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
-            return this.rows[y >> 4].add(this.rows, x, y, z);
+            return this.rows[y >> 4].add(this.rows, x, y, z, minSectionIndex, maxSectionIndex);
         }
 
         @Override
         public void clear(IRow[] parent, int x, int y, int z) {
-            this.rows[y >> 4].set(this.rows, x, y, z);
+            // min/amx layer does not matter here.
+            this.rows[y >> 4].set(this.rows, x, y, z, 0, 0);
         }
 
         @Override
@@ -957,9 +958,7 @@ public final class MemBlockSet extends BlockSet {
         }
 
         public void reset() {
-            for (int i = 0; i < FaweCache.IMP.CHUNK_LAYERS; i++) {
+            Arrays.fill(rows, NULL_ROW_Y);
-                rows[i] = NULL_ROW_Y;
-            }
         }
 
     }
@@ -983,13 +982,13 @@ public final class MemBlockSet extends BlockSet {
         }
 
         @Override
-        public void set(IRow[] parent, int x, int y, int z) {
+        public void set(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
             int i = ((y & 15) << 8) | ((z & 15) << 4) | (x & 15);
             bits[i >> 6] |= (1L << (i & 0x3F));
         }
 
         @Override
-        public boolean add(IRow[] parent, int x, int y, int z) {
+        public boolean add(IRow[] parent, int x, int y, int z, int minSectionIndex, int maxSectionIndex) {
             int i = ((y & 15) << 8) | ((z & 15) << 4) | (x & 15);
             int offset = i >> 6;
             long value = bits[offset];

worldedit-core/src/main/java/com/fastasyncworldedit/core/world/SimpleWorld.java

@@ -61,6 +61,11 @@ public interface SimpleWorld extends World {
         return getMaximumPoint().getBlockY();
     }
 
+    @Override
+    default int getMinY() {
+        return getMinimumPoint().getBlockY();
+    }
+
     @Override
     default Mask createLiquidMask() {
         return new BlockMask(this).add(BlockTypes.LAVA, BlockTypes.WATER);

worldedit-core/src/main/java/com/fastasyncworldedit/core/wrappers/AsyncPlayer.java

@@ -85,8 +85,8 @@ public class AsyncPlayer extends PlayerProxy {
     public boolean ascendToCeiling(int clearance, boolean alwaysGlass) {
         Location pos = getBlockLocation();
         int x = pos.getBlockX();
-        int initialY = Math.max(0, pos.getBlockY());
+        int initialY = Math.max(getWorld().getMinY(), pos.getBlockY());
-        int y = Math.max(0, pos.getBlockY() + 2);
+        int y = Math.max(getWorld().getMinY(), pos.getBlockY() + 2);
         int z = pos.getBlockZ();
         Extent world = getLocation().getExtent();
 
@@ -121,15 +121,15 @@ public class AsyncPlayer extends PlayerProxy {
     public boolean ascendUpwards(int distance, boolean alwaysGlass) {
         final Location pos = getBlockLocation();
         final int x = pos.getBlockX();
-        final int initialY = Math.max(0, pos.getBlockY());
+        final int initialY = Math.max(getWorld().getMinY(), pos.getBlockY());
-        int y = Math.max(0, pos.getBlockY() + 1);
+        int y = Math.max(getWorld().getMinY(), pos.getBlockY() + 1);
         final int z = pos.getBlockZ();
         final int maxY = Math.min(getWorld().getMaxY() + 1, initialY + distance);
         final Extent world = getLocation().getExtent();
 
         MutableBlockVector3 mutable = new MutableBlockVector3(x, y, z);
 
-        while (y <= world.getMaximumPoint().getY() + 2) {
+        while (y <= world.getMaxY() + 2) {
             if (world.getBlock(mutable.mutY(y)).getBlockType().getMaterial()
                     .isMovementBlocker()) {
                 break; // Hit something

worldedit-core/src/main/java/com/fastasyncworldedit/core/wrappers/WorldWrapper.java

@@ -96,6 +96,11 @@ public class WorldWrapper extends AbstractWorld {
         return parent.getMaxY();
     }
 
+    @Override
+    public int getMinY() {
+        return parent.getMinY();
+    }
+
     @Override
     public Mask createLiquidMask() {
         return parent.createLiquidMask();

worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java

@@ -1184,6 +1184,16 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         return getBlockChangeCount();
     }
 
+    @Override
+    public BlockVector3 getMinimumPoint() {
+        return getWorld().getMinimumPoint();
+    }
+
+    @Override
+    public BlockVector3 getMaximumPoint() {
+        return getWorld().getMaximumPoint();
+    }
+
     //FAWE start
     public void setSize(int size) {
         this.changes = size;
@@ -1276,7 +1286,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
     public <B extends BlockStateHolder<B>> int fall(final Region region, boolean fullHeight, final B replace) {
         FlatRegion flat = asFlatRegion(region);
         final int startPerformY = region.getMinimumPoint().getBlockY();
-        final int startCheckY = fullHeight ? 0 : startPerformY;
+        final int startCheckY = fullHeight ? getMinY() : startPerformY;
         final int endY = region.getMaximumPoint().getBlockY();
         RegionVisitor visitor = new RegionVisitor(flat, pos -> {
             int x = pos.getX();
@@ -1353,7 +1363,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         final BlockReplace replace = new BlockReplace(EditSession.this, pattern);
 
         // Pick how we're going to visit blocks
-        RecursiveVisitor visitor = new DirectionalVisitor(mask, replace, origin, direction, (int) (radius * 2 + 1));
+        RecursiveVisitor visitor = new DirectionalVisitor(mask, replace, origin, direction, (int) (radius * 2 + 1), minY, maxY);
 
         // Start at the origin
         visitor.visit(origin);
@@ -1406,8 +1416,8 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         Mask mask = new MaskIntersection(
                 new RegionMask(new EllipsoidRegion(null, origin, Vector3.at(radius, radius, radius))),
                 new BoundedHeightMask(
-                        Math.max(origin.getBlockY() - depth + 1, getMinimumPoint().getBlockY()),
+                        Math.max(origin.getBlockY() - depth + 1, minY),
-                        Math.min(getMaxY(), origin.getBlockY())
+                        Math.min(maxY, origin.getBlockY())
                 ),
                 Masks.negate(new ExistingBlockMask(this))
         );
@@ -1417,11 +1427,11 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
 
         // Pick how we're going to visit blocks
         RecursiveVisitor visitor;
-        //FAWE start - provide extent for preloading
+        //FAWE start - provide extent for preloading, min/max y
         if (recursive) {
-            visitor = new RecursiveVisitor(mask, replace, (int) (radius * 2 + 1), this);
+            visitor = new RecursiveVisitor(mask, replace, (int) (radius * 2 + 1), minY, maxY, this);
         } else {
-            visitor = new DownwardVisitor(mask, replace, origin.getBlockY(), (int) (radius * 2 + 1), this);
+            visitor = new DownwardVisitor(mask, replace, origin.getBlockY(), (int) (radius * 2 + 1), minY, maxY, this);
         }
         //FAWE end
 
@@ -1938,7 +1948,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
             //FAWE end
         }
         Mask mask = new MaskIntersection(
-                new BoundedHeightMask(getWorld().getMinY(), getWorld().getMaxY()),
+                new BoundedHeightMask(minY, maxY),
                 new RegionMask(new EllipsoidRegion(null, origin, Vector3.at(radius, radius, radius))),
                 //FAWE start
                 liquidMask
@@ -1950,8 +1960,8 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         } else {
             replace = new BlockReplace(this, BlockTypes.AIR.getDefaultState());
         }
-        //FAWE start - provide extent for preloading
+        //FAWE start - provide extent for preloading, min/max y
-        RecursiveVisitor visitor = new RecursiveVisitor(mask, replace, (int) (radius * 2 + 1), this);
+        RecursiveVisitor visitor = new RecursiveVisitor(mask, replace, (int) (radius * 2 + 1), minY, maxY, this);
         //FAWE end
 
         // Around the origin in a 3x3 block
@@ -1989,14 +1999,14 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
 
         // There are boundaries that the routine needs to stay in
         Mask mask = new MaskIntersection(
-                new BoundedHeightMask(getWorld().getMinY(), Math.min(origin.getBlockY(), getWorld().getMaxY())),
+                    new BoundedHeightMask(minY, Math.min(origin.getBlockY(), maxY)),
                 new RegionMask(new EllipsoidRegion(null, origin, Vector3.at(radius, radius, radius))),
                 blockMask
         );
 
         BlockReplace replace = new BlockReplace(this, fluid.getDefaultState());
-        //FAWE start - provide extent for preloading
+        //FAWE start - provide extent for preloading, world min/maxY
-        NonRisingVisitor visitor = new NonRisingVisitor(mask, replace, Integer.MAX_VALUE, this);
+        NonRisingVisitor visitor = new NonRisingVisitor(mask, replace, Integer.MAX_VALUE, minY, maxY, this);
         //FAWE end
 
         // Around the origin in a 3x3 block
@@ -2411,7 +2421,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                             }
                         }
                     }
-                    if (y != 0 && (yy = py - y) >= 0) {
+                    if (y != 0 && (yy = py - y) >= minY) {
                         this.setBlock(px + x, yy, pz + z, block);
                         if (x != 0) {
                             this.setBlock(px - x, yy, pz + z, block);
@@ -2506,9 +2516,9 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         BlockState air = BlockTypes.AIR.getDefaultState();
         BlockState water = BlockTypes.WATER.getDefaultState();
 
-        int centerY = Math.max(getWorld().getMinY(), Math.min(getWorld().getMaxY(), oy));
+        int centerY = Math.max(minY, Math.min(maxY, oy));
-        int minY = Math.max(getWorld().getMinY(), centerY - height);
+        int minY = Math.max(this.minY, centerY - height);
-        int maxY = Math.min(getWorld().getMaxY(), centerY + height);
+        int maxY = Math.min(this.maxY, centerY + height);
 
         //FAWE start - mutable
         MutableBlockVector3 mutable = new MutableBlockVector3();
@@ -2535,8 +2545,9 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                             ++affected;
                         }
                     } else if (id == BlockTypes.SNOW) {
+                        //FAWE start
                         if (setBlock(mutable, air)) {
-                            if (y > 0) {
+                            if (y > getMinY()) {
                                 BlockState block = getBlock(mutable2);
                                 if (block.getStates().containsKey(snowy)) {
                                     if (setBlock(mutable2, block.with(snowy, false))) {
@@ -2649,9 +2660,9 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
 
         final BlockState grass = BlockTypes.GRASS_BLOCK.getDefaultState();
 
-        final int centerY = Math.max(getWorld().getMinY(), Math.min(getWorld().getMaxY(), oy));
+        final int centerY = Math.max(minY, Math.min(maxY, oy));
-        final int minY = Math.max(getWorld().getMinY(), centerY - height);
+        final int minY = Math.max(this.minY, centerY - height);
-        final int maxY = Math.min(getWorld().getMaxY(), centerY + height);
+        final int maxY = Math.min(this.maxY, centerY + height);
 
         //FAWE start - mutable
         MutableBlockVector3 mutable = new MutableBlockVector3();
@@ -2952,7 +2963,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                 int zv = (int) (z.getValue() * unit.getZ() + zero2.getZ());
 
                 BlockState get;
-                if (yv >= 0 && yv < 256) {
+                if (yv >= minY && yv <= maxY) {
                     get = getBlock(xv, yv, zv);
                 } else {
                     get = BlockTypes.AIR.getDefaultState();
@@ -3538,7 +3549,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                         int xx = x + bx;
                         for (int z = 0; z < 16; z++) {
                             int zz = z + bz;
-                            for (int y = 0; y < maxY + 1; y++) {
+                            for (int y = minY; y < maxY + 1; y++) {
                                 BaseBlock block = getFullBlock(mutable.setComponents(xx, y, zz));
                                 fcs.add(mutable, block, BlockTypes.AIR.getDefaultState().toBaseBlock());
                             }
@@ -3561,7 +3572,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
                     for (int z = 0; z < 16; z++) {
                         int zz = z + bz;
                         mutable.mutZ(zz);
-                        for (int y = 0; y < maxY + 1; y++) {
+                        for (int y = minY; y < maxY + 1; y++) {
                             mutable.mutY(y);
                             boolean contains = (fe == null || fe.contains(xx, y, zz)) && region.contains(mutable);
                             if (contains) {

worldedit-core/src/main/java/com/sk89q/worldedit/LocalSession.java

@@ -211,6 +211,13 @@ public class LocalSession implements TextureHolder {
         if (defaultSelector != null) {
             this.selector = defaultSelector.createSelector();
         }
+        //FAWE start
+        if (worldOverride != null) {
+            this.selector.setWorld(worldOverride);
+        } else {
+            this.selector.setWorld(currentWorld);
+        }
+        //FAWE end
     }
 
     //FAWE start

worldedit-core/src/main/java/com/sk89q/worldedit/command/BrushCommands.java

@@ -457,6 +457,7 @@ public class BrushCommands {
     )
     @CommandPermissions("worldedit.brush.stencil")
     public void stencilBrush(
+            Player player,
             LocalSession session, InjectedValueAccess context,
             @Arg(desc = "Pattern")
                     Pattern fill,
@@ -478,13 +479,15 @@ public class BrushCommands {
         worldEdit.checkMaxBrushRadius(radius);
         InputStream stream = getHeightmapStream(image);
         HeightBrush brush;
+        int minY = player.getWorld().getMinY();
+        int maxY = player.getWorld().getMaxY();
         try {
             brush = new StencilBrush(stream, rotation, yscale, onlyWhite,
                     "#clipboard".equalsIgnoreCase(image)
-                            ? session.getClipboard().getClipboard() : null
+                            ? session.getClipboard().getClipboard() : null, minY, maxY
             );
         } catch (EmptyClipboardException ignored) {
-            brush = new StencilBrush(stream, rotation, yscale, onlyWhite, null);
+            brush = new StencilBrush(stream, rotation, yscale, onlyWhite, null, minY, maxY);
         }
         if (randomRotate) {
             brush.setRandomRotate(true);
@@ -710,6 +713,7 @@ public class BrushCommands {
     )
     @CommandPermissions("worldedit.brush.height")
     public void heightBrush(
+            Player player,
             LocalSession session,
             @Arg(desc = "Expression", def = "5")
                     Expression radius,
@@ -728,7 +732,7 @@ public class BrushCommands {
                     boolean dontSmooth, InjectedValueAccess context
     )
             throws WorldEditException, FileNotFoundException {
-        terrainBrush(session, radius, image, rotation, yscale, false, randomRotate, layers,
+        terrainBrush(player, session, radius, image, rotation, yscale, false, randomRotate, layers,
                 !dontSmooth, ScalableHeightMap.Shape.CONE, context
         );
     }
@@ -741,6 +745,7 @@ public class BrushCommands {
     )
     @CommandPermissions("worldedit.brush.height")
     public void cliffBrush(
+            Player player,
             LocalSession session,
             @Arg(desc = "Expression", def = "5")
                     Expression radius,
@@ -760,7 +765,7 @@ public class BrushCommands {
                     boolean dontSmooth, InjectedValueAccess context
     )
             throws WorldEditException, FileNotFoundException {
-        terrainBrush(session, radius, image, rotation, yscale, true, randomRotate, layers,
+        terrainBrush(player, session, radius, image, rotation, yscale, true, randomRotate, layers,
                 !dontSmooth, ScalableHeightMap.Shape.CYLINDER, context
         );
     }
@@ -775,6 +780,7 @@ public class BrushCommands {
     )
     @CommandPermissions("worldedit.brush.height")
     public void flattenBrush(
+            Player player,
             LocalSession session,
             @Arg(desc = "Expression", def = "5")
                     Expression radius,
@@ -794,12 +800,13 @@ public class BrushCommands {
                     boolean dontSmooth, InjectedValueAccess context
     )
             throws WorldEditException, FileNotFoundException {
-        terrainBrush(session, radius, image, rotation, yscale, true, randomRotate, layers,
+        terrainBrush(player, session, radius, image, rotation, yscale, true, randomRotate, layers,
                 !dontSmooth, ScalableHeightMap.Shape.CONE, context
         );
     }
 
     private void terrainBrush(
+            Player player,
             LocalSession session,
             Expression radius,
             String image,
@@ -816,23 +823,25 @@ public class BrushCommands {
         worldEdit.checkMaxBrushRadius(radius);
         InputStream stream = getHeightmapStream(image);
         HeightBrush brush;
+        int minY = player.getWorld().getMinY();
+        int maxY = player.getWorld().getMaxY();
         if (flat) {
             try {
                 brush = new FlattenBrush(stream, rotation, yscale, layers, smooth,
                         "#clipboard".equalsIgnoreCase(image)
-                                ? session.getClipboard().getClipboard() : null, shape
+                                ? session.getClipboard().getClipboard() : null, shape, minY, maxY
                 );
             } catch (EmptyClipboardException ignored) {
-                brush = new FlattenBrush(stream, rotation, yscale, layers, smooth, null, shape);
+                brush = new FlattenBrush(stream, rotation, yscale, layers, smooth, null, shape, minY, maxY);
             }
         } else {
             try {
                 brush = new HeightBrush(stream, rotation, yscale, layers, smooth,
                         "#clipboard".equalsIgnoreCase(image)
-                                ? session.getClipboard().getClipboard() : null
+                                ? session.getClipboard().getClipboard() : null, minY, maxY
                 );
             } catch (EmptyClipboardException ignored) {
-                brush = new HeightBrush(stream, rotation, yscale, layers, smooth, null);
+                brush = new HeightBrush(stream, rotation, yscale, layers, smooth, null, minY, maxY);
             }
         }
         if (randomRotate) {

worldedit-core/src/main/java/com/sk89q/worldedit/command/GenerationCommands.java

@@ -635,12 +635,18 @@ public class GenerationCommands {
             @Arg(desc = "Ore vein size") @Range(from = 0, to = Integer.MAX_VALUE) int size,
             @Arg(desc = "Ore vein frequency (number of times to attempt to place ore)", def = "10") @Range(from = 0, to = Integer.MAX_VALUE) int freq,
             @Arg(desc = "Ore vein rarity (% chance each attempt is placed)", def = "100") @Range(from = 0, to = 100) int rarity,
-            @Arg(desc = "Ore vein min y", def = "0") @Range(from = 0, to = 255) int minY,
+            @Arg(desc = "Ore vein min y", def = "0") int minY,
-            @Arg(desc = "Ore vein max y", def = "63") @Range(from = 0, to = 255) int maxY
+            @Arg(desc = "Ore vein max y", def = "63") int maxY
     ) throws WorldEditException {
         if (mask instanceof AbstractExtentMask) {
             ((AbstractExtentMask) mask).setExtent(editSession);
         }
+        checkCommandArgument(minY >= editSession.getMinY(), Caption.of("fawe.error.outside-range-lower", "miny",
+                editSession.getMinY()));
+        checkCommandArgument(maxY <= editSession.getMaxY(), Caption.of("fawe.error.outside-range-upper", "maxy",
+                editSession.getMaxY()));
+        checkCommandArgument(minY < maxY, Caption.of("fawe.error.argument-size-mismatch", "miny",
+                "maxy"));
         editSession.addOre(region, mask, material, size, freq, rarity, minY, maxY);
         actor.print(Caption.of("fawe.worldedit.visitor.visitor.block", editSession.getBlockChangeCount()));
     }

worldedit-core/src/main/java/com/sk89q/worldedit/command/HistorySubCommands.java

@@ -133,8 +133,8 @@ public class HistorySubCommands {
         Location origin = player.getLocation();
         BlockVector3 bot = origin.toBlockPoint().subtract(radius, radius, radius);
         BlockVector3 top = origin.toBlockPoint().add(radius, radius, radius);
-        bot = bot.clampY(0, world.getMaxY());
+        bot = bot.clampY(world.getMinY(), world.getMaxY());
-        top = top.clampY(0, world.getMaxY());
+        top = top.clampY(world.getMinY(), world.getMaxY());
         // TODO mask the regions bot / top to the bottom and top coord in the allowedRegions
         // TODO: then mask the edit to the bot / top
         //        if (allowedRegions.length != 1 || !allowedRegions[0].isGlobal()) {
@@ -196,9 +196,9 @@ public class HistorySubCommands {
                                             .summarize(RegionWrapper.GLOBAL(), false);
                                     if (summary != null) {
                                         rollback.setDimensions(
-                                                BlockVector3.at(summary.minX, 0, summary.minZ),
+                                                BlockVector3.at(summary.minX, world.getMinY(), summary.minZ),
                                                 BlockVector3
-                                                        .at(summary.maxX, 255, summary.maxZ)
+                                                        .at(summary.maxX, world.getMaxY(), summary.maxZ)
                                         );
                                         rollback.setTime(historyFile.lastModified());
                                         RollbackDatabase db = DBHandler.IMP
@@ -410,8 +410,8 @@ public class HistorySubCommands {
 
             BlockVector3 bot = origin.toBlockPoint().subtract(radius, radius, radius);
             BlockVector3 top = origin.toBlockPoint().add(radius, radius, radius);
-            bot = bot.clampY(0, world.getMaxY());
+            bot = bot.clampY(world.getMinY(), world.getMaxY());
-            top = top.clampY(0, world.getMaxY());
+            top = top.clampY(world.getMinY(), world.getMaxY());
 
             long minTime = System.currentTimeMillis() - timeDiff;
             Iterable<Supplier<RollbackOptimizedHistory>> edits = database.getEdits(other, minTime, bot, top, false, false);

worldedit-core/src/main/java/com/sk89q/worldedit/command/RegionCommands.java

@@ -363,17 +363,23 @@ public class RegionCommands {
             @Selection Region region,
             @Arg(name = "pattern", desc = "The pattern of blocks to lay") Pattern patternArg
     ) throws WorldEditException {
-        BlockVector3 max = region.getMaximumPoint();
+        //FAWE start - world min/maxY
-        int maxY = max.getBlockY();
+        int maxY = region.getMaximumY();
+        int minY = region.getMinimumY();
+        //FAWE end
         Iterable<BlockVector2> flat = Regions.asFlatRegion(region).asFlatRegion();
         Iterator<BlockVector2> iter = flat.iterator();
-        int y = 0;
+        //FAWE start - world min/maxY
+        int y = minY;
+        //FAWE end
         int affected = 0;
         while (iter.hasNext()) {
             BlockVector2 pos = iter.next();
             int x = pos.getBlockX();
             int z = pos.getBlockZ();
-            y = editSession.getNearestSurfaceTerrainBlock(x, z, y, 0, maxY);
+            //FAWE start - world min/maxY
+            y = editSession.getNearestSurfaceTerrainBlock(x, z, y, minY, maxY);
+            //FAWE end
             editSession.setBlock(x, y, z, patternArg);
             affected++;
         }
@@ -856,6 +862,7 @@ public class RegionCommands {
     )
     @CommandPermissions("worldedit.region.flora")
     @Logging(REGION)
+    @Preload(Preload.PreloadCheck.PRELOAD)
     @Confirm(Confirm.Processor.REGION)
     public int flora(
             Actor actor, EditSession editSession, @Selection Region region,
@@ -867,7 +874,7 @@ public class RegionCommands {
         FloraGenerator generator = new FloraGenerator(editSession);
         GroundFunction ground = new GroundFunction(new ExistingBlockMask(editSession), generator);
         //FAWE start - provide extent for preloading
-        LayerVisitor visitor = new LayerVisitor(asFlatRegion(region), minimumBlockY(region), maximumBlockY(region), ground, editSession);
+        LayerVisitor visitor = new LayerVisitor(asFlatRegion(region), minimumBlockY(region), maximumBlockY(region), ground);
         //FAWE end
         visitor.setMask(new NoiseFilter2D(new RandomNoise(), density));
         Operations.completeLegacy(visitor);

worldedit-core/src/main/java/com/sk89q/worldedit/command/SelectionCommands.java

@@ -124,9 +124,9 @@ public class SelectionCommands {
         Location pos;
         //FAWE start - clamp
         if (coordinates != null) {
-            pos = new Location(world, coordinates.toVector3().clampY(0, world.getMaxY()));
+            pos = new Location(world, coordinates.toVector3().clampY(world.getMinY(), world.getMaxY()));
         } else if (actor instanceof Locatable) {
-            pos = ((Locatable) actor).getBlockLocation().clampY(0, world.getMaxY());
+            pos = ((Locatable) actor).getBlockLocation().clampY(world.getMinY(), world.getMaxY());
             //FAWE end
         } else {
             actor.print(Caption.of("worldedit.pos.console-require-coords"));
@@ -157,9 +157,9 @@ public class SelectionCommands {
         Location pos;
         if (coordinates != null) {
             //FAWE start - clamp
-            pos = new Location(world, coordinates.toVector3().clampY(0, world.getMaxY()));
+            pos = new Location(world, coordinates.toVector3().clampY(world.getMinY(), world.getMaxY()));
         } else if (actor instanceof Locatable) {
-            pos = ((Locatable) actor).getBlockLocation().clampY(0, world.getMaxY());
+            pos = ((Locatable) actor).getBlockLocation().clampY(world.getMinY(), world.getMaxY());
             //Fawe end
         } else {
             actor.print(Caption.of("worldedit.pos.console-require-coords"));
@@ -258,7 +258,7 @@ public class SelectionCommands {
                     .clampY(minChunkY, maxChunkY);
 
             min = minChunk.shl(CHUNK_SHIFTS, CHUNK_SHIFTS_Y, CHUNK_SHIFTS);
-            max = maxChunk.shl(CHUNK_SHIFTS, CHUNK_SHIFTS_Y, CHUNK_SHIFTS).add(15, world.getMaxY(), 15);
+            max = maxChunk.shl(CHUNK_SHIFTS, CHUNK_SHIFTS_Y, CHUNK_SHIFTS).add(15, 255, 15);
 
             actor.print(Caption.of(
                     "worldedit.chunk.selected-multiple",
@@ -286,7 +286,7 @@ public class SelectionCommands {
             }
 
             min = minChunk.shl(CHUNK_SHIFTS, CHUNK_SHIFTS_Y, CHUNK_SHIFTS);
-            max = min.add(15, world.getMaxY(), 15);
+            max = min.add(15, 255, 15);
 
             actor.print(Caption.of(
                     "worldedit.chunk.selected",

worldedit-core/src/main/java/com/sk89q/worldedit/command/UtilityCommands.java

@@ -413,8 +413,8 @@ public class UtilityCommands {
     ) throws WorldEditException {
         size = Math.max(1, size);
         we.checkMaxRadius(size);
-        height = height != null ? Math.min((world.getMaxY() + 1), height + 1) : (world.getMaxY() + 1);
 
+        height = height != null ? Math.min((world.getMaxY() - world.getMinY() + 1), height + 1) : (world.getMaxY() - world.getMinY() + 1);
         int affected = editSession.removeAbove(session.getPlacementPosition(actor), size, height);
         actor.print(Caption.of("worldedit.removeabove.removed", TextComponent.of(affected)));
         return affected;
@@ -436,8 +436,8 @@ public class UtilityCommands {
     ) throws WorldEditException {
         size = Math.max(1, size);
         we.checkMaxRadius(size);
-        height = height != null ? Math.min((world.getMaxY() + 1), height + 1) : (world.getMaxY() + 1);
 
+        height = height != null ? Math.min((world.getMaxY() - world.getMinY() + 1), height + 1) : (world.getMaxY() - world.getMinY() + 1);
         int affected = editSession.removeBelow(session.getPlacementPosition(actor), size, height);
         actor.print(Caption.of("worldedit.removebelow.removed", TextComponent.of(affected)));
         return affected;

worldedit-core/src/main/java/com/sk89q/worldedit/command/tool/BrushTool.java

@@ -388,7 +388,7 @@ public class BrushTool
                 final int x = loc.getBlockX();
                 final int z = loc.getBlockZ();
                 int y;
-                for (y = height; y > 0; y--) {
+                for (y = height; y > editSession.getMinY(); y--) {
                     BlockType block = editSession.getBlockType(x, y, z);
                     if (block.getMaterial().isMovementBlocker()) {
                         break;

worldedit-core/src/main/java/com/sk89q/worldedit/command/tool/FloodFillTool.java

@@ -87,7 +87,8 @@ public class FloodFillTool implements BlockTool {
                 //FAWE start - Respect masks
                 Mask mask = initialType.toMask(editSession);
                 BlockReplace function = new BlockReplace(editSession, pattern);
-                RecursiveVisitor visitor = new RecursiveVisitor(mask, function, range, editSession);
+                RecursiveVisitor visitor = new RecursiveVisitor(mask, function, range, editSession.getMinY(),
+                        editSession.getMaxY(), editSession);
                 visitor.visit(origin);
                 Operations.completeLegacy(visitor);
                 //FAWE end

worldedit-core/src/main/java/com/sk89q/worldedit/command/tool/RecursivePickaxe.java

@@ -86,7 +86,14 @@ public class RecursivePickaxe implements BlockTool {
             final int radius = (int) range;
             final BlockReplace replace = new BlockReplace(editSession, (BlockTypes.AIR.getDefaultState()));
             editSession.setMask(null);
-            RecursiveVisitor visitor = new RecursiveVisitor(new IdMask(editSession), replace, radius, editSession);
+            RecursiveVisitor visitor = new RecursiveVisitor(
+                    new IdMask(editSession),
+                    replace,
+                    radius,
+                    editSession.getMinY(),
+                    editSession.getMaxY(),
+                    editSession
+            );
             //TODO: Fix below
             //visitor.visit(pos);
             //Operations.completeBlindly(visitor);

worldedit-core/src/main/java/com/sk89q/worldedit/command/tool/brush/GravityBrush.java

@@ -39,8 +39,8 @@ public class GravityBrush implements Brush {
             MaxChangedBlocksException {
         //FAWE start - Ours operates differently to upstream, but does the same
         double endY = position.getY() + size;
-        double startPerformY = Math.max(0, position.getY() - size);
+        double startPerformY = Math.max(editSession.getMinY(), position.getY() - size);
-        double startCheckY = fullHeight ? 0 : startPerformY;
+        double startCheckY = fullHeight ? editSession.getMinY() : startPerformY;
         for (double x = position.getX() + size; x > position.getX() - size; --x) {
             for (double z = position.getZ() + size; z > position.getZ() - size; --z) {
                 double freeSpot = startCheckY;

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/parser/mask/OffsetMaskParser.java

@@ -69,7 +69,7 @@ public class OffsetMaskParser extends InputParser<Mask> implements AliasedParser
             submask = new ExistingBlockMask(context.requireExtent());
         }
         //FAWE start - OffsetMask > OffsetsMask
-        return new OffsetMask(submask, BlockVector3.at(0, firstChar == '>' ? -1 : 1, 0));
+        return new OffsetMask(submask, BlockVector3.at(0, firstChar == '>' ? -1 : 1, 0), context.getMinY(), context.getMaxY());
         //FAWE end
     }
 

worldedit-core/src/main/java/com/sk89q/worldedit/extension/input/ParserContext.java

@@ -23,6 +23,7 @@ import com.fastasyncworldedit.core.configuration.Caption;
 import com.sk89q.worldedit.LocalSession;
 import com.sk89q.worldedit.extension.factory.MaskFactory;
 import com.sk89q.worldedit.extension.platform.Actor;
+import com.sk89q.worldedit.extension.platform.Locatable;
 import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.world.World;
 import org.enginehub.piston.inject.InjectedValueAccess;
@@ -50,6 +51,8 @@ public class ParserContext {
     private boolean preferringWildcard;
     //Fawe start
     private InjectedValueAccess injected;
+    private int minY = Integer.MIN_VALUE;
+    private int maxY = Integer.MAX_VALUE;
     //FAWE end
 
     /**
@@ -270,5 +273,69 @@ public class ParserContext {
     public InjectedValueAccess getInjected() {
         return injected;
     }
+
+    /**
+     * Attempts to resolve the minimum Y value associated with this context or returns 0.
+     * Caches both min and max y values.
+     *
+     * @return Minimum y value (inclusive) or 0
+     */
+    public int getMinY() {
+        if (minY != Integer.MIN_VALUE) {
+            return minY;
+        }
+
+        Extent extent = null;
+
+        if (actor instanceof Locatable) {
+            extent = ((Locatable) actor).getExtent();
+        } else if (world != null) {
+            extent = world;
+        } else if (this.extent != null) {
+            extent = this.extent;
+        }
+
+        if (extent != null) {
+            minY = extent.getMinY();
+            maxY = extent.getMaxY();
+        } else {
+            minY = 0;
+            maxY = 255;
+        }
+
+        return minY;
+    }
+
+    /**
+     * Attempts to resolve the maximum Y value associated with this context or returns 255.
+     * Caches both min and max y values.
+     *
+     * @return Maximum y value (inclusive) or 255
+     */
+    public int getMaxY() {
+        if (maxY != Integer.MAX_VALUE) {
+            return maxY;
+        }
+
+        Extent extent = null;
+
+        if (actor instanceof Locatable) {
+            extent = ((Locatable) actor).getExtent();
+        } else if (world != null) {
+            extent = world;
+        } else if (this.extent != null) {
+            extent = this.extent;
+        }
+
+        if (extent != null) {
+            minY = extent.getMinY();
+            maxY = extent.getMaxY();
+        } else {
+            minY = 0;
+            maxY = 255;
+        }
+
+        return maxY;
+    }
     //FAWE end
 }

worldedit-core/src/main/java/com/sk89q/worldedit/extent/AbstractDelegateExtent.java

@@ -202,6 +202,11 @@ public class AbstractDelegateExtent implements Extent {
         return extent.getMaxY();
     }
 
+    @Override
+    public int getMinY() {
+        return extent.getMinY();
+    }
+
     @Override
     public boolean relight(int x, int y, int z) {
         return extent.relight(x, y, z);
@@ -317,7 +322,7 @@ public class AbstractDelegateExtent implements Extent {
 
     @Override
     public <T extends BlockStateHolder<T>> boolean setBlock(
-            int x, @Range(from = 0, to = 255) int y,
+            int x, int y,
             int z, T block
     ) throws WorldEditException {
         return extent.setBlock(x, y, z, block);

worldedit-core/src/main/java/com/sk89q/worldedit/extent/Extent.java

@@ -200,9 +200,16 @@ public interface Extent extends InputExtent, OutputExtent {
          - TODO: actually optimize these
      */
 
+    /**
+     * Returns the highest solid 'terrain' block.
+     *
+     * @param x    the X coordinate
+     * @param z    the Z coordinate
+     * @param minY minimal height
+     * @param maxY maximal height
+     * @return height of highest block found or 'minY'
+     */
     default int getHighestTerrainBlock(final int x, final int z, int minY, int maxY) {
-        maxY = Math.min(maxY, Math.max(0, maxY));
-        minY = Math.max(0, minY);
         for (int y = maxY; y >= minY; --y) {
             BlockState block = getBlock(x, y, z);
             if (block.getBlockType().getMaterial().isMovementBlocker()) {
@@ -212,9 +219,19 @@ public interface Extent extends InputExtent, OutputExtent {
         return minY;
     }
 
+    /**
+     * Returns the highest solid 'terrain' block.
+     *
+     * @param x      the X coordinate
+     * @param z      the Z coordinate
+     * @param minY   minimal height
+     * @param maxY   maximal height
+     * @param filter a mask of blocks to consider, or null to consider any solid (movement-blocking) block
+     * @return height of highest block found or 'minY'
+     */
     default int getHighestTerrainBlock(final int x, final int z, int minY, int maxY, Mask filter) {
-        maxY = Math.min(maxY, Math.max(0, maxY));
+        maxY = Math.min(maxY, getMaxY());
-        minY = Math.max(0, minY);
+        minY = Math.max(getMinY(), minY);
 
         MutableBlockVector3 mutable = new MutableBlockVector3();
 
@@ -226,6 +243,18 @@ public interface Extent extends InputExtent, OutputExtent {
         return minY;
     }
 
+    /**
+     * Returns the nearest surface layer (up/down from start)
+     * <p>
+     * TODO: Someone understand this..?
+     *
+     * @param x    x to search from
+     * @param z    y to search from
+     * @param y    z to search from
+     * @param minY min y to search (inclusive)
+     * @param maxY max y to search (inclusive)
+     * @return nearest surface layer
+     */
     default int getNearestSurfaceLayer(int x, int z, int y, int minY, int maxY) {
         int clearanceAbove = maxY - y;
         int clearanceBelow = y - minY;
@@ -255,7 +284,7 @@ public interface Extent extends InputExtent, OutputExtent {
                 for (int layer = y - clearance - 1; layer >= minY; layer--) {
                     block = getBlock(x, layer, z);
                     if (block.getBlockType().getMaterial().isMovementBlocker() == state) {
-                        return ((layer + offset) << 4) + 0;
+                        return (layer + offset) << 4;
                     }
                     data1 = PropertyGroup.LEVEL.get(block);
                 }
@@ -272,18 +301,20 @@ public interface Extent extends InputExtent, OutputExtent {
         return (state ? minY : maxY) << 4;
     }
 
-    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, boolean ignoreAir) {
+    /**
-        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, minY, maxY, ignoreAir);
+     * Gets y value for the nearest block that is considered the surface of the terrain (cave roof/floor, mountain surface,
-    }
+     * etc) where the block conforms to a given mask. Searches in the x,z column given.
-
+     *
-    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY) {
+     * @param x         column x
-        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, minY, maxY);
+     * @param z         column z
-    }
+     * @param y         start y
-
+     * @param minY      minimum y height to consider. Inclusive.
-    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax) {
+     * @param maxY      maximum y height to consider. Inclusive.
-        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, failedMin, failedMax, true);
+     * @param failedMin if nothing found, the minimum y value to return if returning min
-    }
+     * @param failedMax if nothing found, the maximum y value to return if returning max
-
+     * @param mask      mask to test blocks against
+     * @return The y value of the nearest terrain block
+     */
     default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax, Mask mask) {
         y = Math.max(minY, Math.min(maxY, y));
         int clearanceAbove = maxY - y;
@@ -320,6 +351,68 @@ public interface Extent extends InputExtent, OutputExtent {
         return state ? failedMin : failedMax;
     }
 
+    /**
+     * Gets y value for the nearest block that is considered the surface of the terrain (cave roof/floor, mountain surface,
+     * etc). Searches in the x,z column given.
+     *
+     * @param x         column x
+     * @param z         column z
+     * @param y         start y
+     * @param minY      minimum y height to consider. Inclusive.
+     * @param maxY      maximum y height to consider. Inclusive.
+     * @param ignoreAir if air at the final value if no block found should be considered for return, else return -1
+     * @return The y value of the nearest terrain block
+     */
+    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, boolean ignoreAir) {
+        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, minY, maxY, ignoreAir);
+    }
+
+    /**
+     * Gets y value for the nearest block that is considered the surface of the terrain (cave roof/floor, mountain surface,
+     * etc). Searches in the x,z column given.
+     *
+     * @param x    column x
+     * @param z    column z
+     * @param y    start y
+     * @param minY minimum y height to consider. Inclusive.
+     * @param maxY maximum y height to consider. Inclusive.
+     * @return The y value of the nearest terrain block
+     */
+    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY) {
+        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, minY, maxY);
+    }
+
+    /**
+     * Gets y value for the nearest block that is considered the surface of the terrain (cave roof/floor, mountain surface,
+     * etc). Searches in the x,z column given.
+     *
+     * @param x         column x
+     * @param z         column z
+     * @param y         start y
+     * @param minY      minimum y height to consider. Inclusive.
+     * @param maxY      maximum y height to consider. Inclusive.
+     * @param failedMin if nothing found, the minimum y value to return if returning min
+     * @param failedMax if nothing found, the maximum y value to return if returning max
+     * @return The y value of the nearest terrain block
+     */
+    default int getNearestSurfaceTerrainBlock(int x, int z, int y, int minY, int maxY, int failedMin, int failedMax) {
+        return getNearestSurfaceTerrainBlock(x, z, y, minY, maxY, failedMin, failedMax, true);
+    }
+
+    /**
+     * Gets y value for the nearest block that is considered the surface of the terrain (cave roof/floor, mountain surface,
+     * etc). Searches in the x,z column given.
+     *
+     * @param x         column x
+     * @param z         column z
+     * @param y         start y
+     * @param minY      minimum y height to consider. Inclusive.
+     * @param maxY      maximum y height to consider. Inclusive.
+     * @param failedMin if nothing found, the minimum y value to return if returning min
+     * @param failedMax if nothing found, the maximum y value to return if returning max
+     * @param ignoreAir if air at the final value if no block found should be considered for return, else return -1
+     * @return The y value of the nearest terrain block
+     */
     default int getNearestSurfaceTerrainBlock(
             int x,
             int z,
@@ -367,7 +460,7 @@ public interface Extent extends InputExtent, OutputExtent {
             }
         }
         int result = state ? failedMin : failedMax;
-        if (result > 0 && !ignoreAir) {
+        if (result > minY && !ignoreAir) {
             block = getBlock(x, result, z);
             return block.getBlockType().getMaterial().isAir() ? -1 : result;
         }
@@ -444,12 +537,13 @@ public interface Extent extends InputExtent, OutputExtent {
         spawnResource(region, new OreGen(this, mask, material, size, minY, maxY), rarity, frequency);
     }
 
+    //TODO: probably update these for 1.18 etc.
     default void addOres(Region region, Mask mask) throws WorldEditException {
-        addOre(region, mask, BlockTypes.DIRT.getDefaultState(), 33, 10, 100, 0, 255);
+        addOre(region, mask, BlockTypes.DIRT.getDefaultState(), 33, 10, 100, getMinY(), getMaxY());
-        addOre(region, mask, BlockTypes.GRAVEL.getDefaultState(), 33, 8, 100, 0, 255);
+        addOre(region, mask, BlockTypes.GRAVEL.getDefaultState(), 33, 8, 100, getMinY(), getMaxY());
-        addOre(region, mask, BlockTypes.ANDESITE.getDefaultState(), 33, 10, 100, 0, 79);
+        addOre(region, mask, BlockTypes.ANDESITE.getDefaultState(), 33, 10, 100, getMinY(), 79);
-        addOre(region, mask, BlockTypes.DIORITE.getDefaultState(), 33, 10, 100, 0, 79);
+        addOre(region, mask, BlockTypes.DIORITE.getDefaultState(), 33, 10, 100, getMinY(), 79);
-        addOre(region, mask, BlockTypes.GRANITE.getDefaultState(), 33, 10, 100, 0, 79);
+        addOre(region, mask, BlockTypes.GRANITE.getDefaultState(), 33, 10, 100, getMinY(), 79);
         addOre(region, mask, BlockTypes.COAL_ORE.getDefaultState(), 17, 20, 100, 0, 127);
         addOre(region, mask, BlockTypes.IRON_ORE.getDefaultState(), 9, 20, 100, 0, 63);
         addOre(region, mask, BlockTypes.GOLD_ORE.getDefaultState(), 9, 2, 100, 0, 31);
@@ -556,11 +650,11 @@ public interface Extent extends InputExtent, OutputExtent {
     }
 
     default int getMinY() {
-        return 0;
+        return getMinimumPoint().getY();
     }
 
     default int getMaxY() {
-        return 255;
+        return getMaximumPoint().getY();
     }
 
     /**

worldedit-core/src/main/java/com/sk89q/worldedit/extent/clipboard/Clipboard.java

@@ -347,7 +347,7 @@ public interface Clipboard extends Extent, Iterable<BlockVector3>, Closeable {
             if (!pasteAir && block.getBlockType().getMaterial().isAir()) {
                 continue;
             }
-            if (pos.getY() < 0) {
+            if (pos.getY() < extent.getMinY()) {
                 throw new RuntimeException("Y-Position cannot be less than 0!");
             }
             extent.setBlock(xx, yy, zz, block);

worldedit-core/src/main/java/com/sk89q/worldedit/function/mask/OffsetMask.java

@@ -31,6 +31,10 @@ import static com.google.common.base.Preconditions.checkNotNull;
  */
 public class OffsetMask extends AbstractMask {
 
+    //FAWE start - ignore resultant position outside world height range
+    private final int minY;
+    private final int maxY;
+    //FAWE end
     private Mask mask;
     private BlockVector3 offset;
 
@@ -39,12 +43,30 @@ public class OffsetMask extends AbstractMask {
      *
      * @param mask   the mask
      * @param offset the offset
+     * @deprecated use {@link OffsetMask#OffsetMask(Mask, BlockVector3, int, int)}
      */
+    @Deprecated
     public OffsetMask(Mask mask, BlockVector3 offset) {
+        this(mask, offset, 0, 255);
+    }
+
+    /**
+     * Create a new instance.
+     *
+     * @param mask   the mask
+     * @param offset the offset
+     * @param minY   minimum allowable y value to be set. Inclusive.
+     * @param maxY   maximum allowable y value to be set. Inclusive.
+     */
+    //FAWE start - ignore resultant position outside world height range
+    public OffsetMask(Mask mask, BlockVector3 offset, int minY, int maxY) {
         checkNotNull(mask);
         checkNotNull(offset);
         this.mask = mask;
         this.offset = offset;
+        this.minY = minY;
+        this.maxY = maxY;
+        //FAWE end
     }
 
     /**
@@ -87,11 +109,13 @@ public class OffsetMask extends AbstractMask {
 
     @Override
     public boolean test(BlockVector3 vector) {
+        //FAWE start - ignore resultant position outside world height range
         BlockVector3 testPos = vector.add(offset);
-        if (testPos.getBlockY() < 0 || testPos.getBlockY() > 255) {
+        if (testPos.getBlockY() < minY || testPos.getBlockY() > maxY) {
             return false;
         }
-        return getMask().test(vector.add(offset));
+        return getMask().test(testPos);
+        //FAWE end
     }
 
     @Nullable
@@ -108,7 +132,7 @@ public class OffsetMask extends AbstractMask {
     //FAWE start
     @Override
     public Mask copy() {
-        return new OffsetMask(mask.copy(), offset.toImmutable());
+        return new OffsetMask(mask.copy(), offset.toImmutable(), minY, maxY);
     }
     //FAWE end