Added //naturalize.

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

@@ -1296,6 +1296,79 @@ public class EditSession {
         return affected;
     }
 
+    /**
+     * Turns the first 3 layers into dirt/grass and the bottom layers
+     * into rock, like a natural Minecraft mountain.
+     *
+     * @param region
+     * @return number of blocks affected
+     * @throws MaxChangedBlocksException
+     */
+    public int naturalizeCuboidBlocks(Region region)
+            throws MaxChangedBlocksException {
+        Vector min = region.getMinimumPoint();
+        Vector max = region.getMaximumPoint();
+
+        int upperY = Math.min(127, max.getBlockY() + 1);
+        int lowerY = Math.max(0, min.getBlockY() - 1);
+
+        int affected = 0;
+
+        int minX = min.getBlockX();
+        int minZ = min.getBlockZ();
+        int maxX = max.getBlockX();
+        int maxZ = max.getBlockZ();
+
+        BaseBlock grass = new BaseBlock(BlockID.GRASS);
+        BaseBlock dirt = new BaseBlock(BlockID.DIRT);
+        BaseBlock stone = new BaseBlock(BlockID.STONE);
+
+        for (int x = minX; x <= maxX; ++x) {
+            for (int z = minZ; z <= maxZ; ++z) {
+                int level = -1;
+
+                for (int y = upperY; y >= lowerY; --y) {
+                    Vector pt = new Vector(x, y, z);
+                    Vector above = new Vector(x, y + 1, z);
+                    int blockType = getBlockType(pt);
+
+                    boolean isTransformable =
+                            blockType == BlockID.GRASS
+                            || blockType == BlockID.DIRT
+                            || blockType == BlockID.STONE;
+
+                    // Still searching for the top block
+                    if (level == -1) {
+                        if (!isTransformable) {
+                            continue; // Not transforming this column yet
+                        }
+
+                        level = 0;
+                    }
+
+                    if (level >= 0) {
+                        if (isTransformable) {
+                            if (level == 0) {
+                                setBlock(pt, grass);
+                                affected++;
+                            } else if (level <= 2) {
+                                setBlock(pt, dirt);
+                                affected++;
+                            } else {
+                                setBlock(pt, stone);
+                                affected++;
+                            }
+                        }
+
+                        level++;
+                    }
+                }
+            }
+        }
+
+        return affected;
+    }
+
     /**
      * Stack a cuboid region.
      * 

src/main/java/com/sk89q/worldedit/commands/RegionCommands.java

@@ -121,6 +121,23 @@ public class RegionCommands {
         player.print(affected + " block(s) have been overlayed.");
     }
 
+    @Command(
+        aliases = {"/naturalize"},
+        usage = "",
+        desc = "3 layers of dirt on top then rock below",
+        min = 0,
+        max = 0
+    )
+    @CommandPermissions({"worldedit.region.naturalize"})
+    public static void naturalize(CommandContext args, WorldEdit we,
+            LocalSession session, LocalPlayer player, EditSession editSession)
+            throws WorldEditException {
+
+        Region region = session.getSelection(player.getWorld());
+        int affected = editSession.naturalizeCuboidBlocks(region);
+        player.print(affected + " block(s) have been naturalized.");
+    }
+
     @Command(
         aliases = {"/walls"},
         usage = "<block>",