diff --git a/src/EditSession.java b/src/EditSession.java
old mode 100644
new mode 100755
index 79b05ca31..47e08c691
--- a/src/EditSession.java
+++ b/src/EditSession.java
@@ -1856,4 +1856,44 @@ public class EditSession {
 
         return distribution;
     }
+    
+    /**
+     * Returns the highest solid 'terrain' block which can occur naturally.
+     * Looks at: 1, 2, 3, 7, 12, 13, 14, 15, 16, 56, 73, 74, 87, 88, 89
+     * 
+     * @param x
+     * @param z
+     * @param minY minimal height
+     * @param maxY maximal height
+     * @return height of highest block found or 'minY'
+     */
+
+    public int getHighestTerrainBlock( int x , int z, int minY, int maxY) {
+        for (int y = maxY; y >= minY; y--) {
+            Vector pt = new Vector(x, y, z);
+            int id = getBlock(pt).getID();
+
+            if (id == 1 // stone
+                    || id == 2 // grass
+                    || id == 3 // dirt
+                    || id == 7 // bedrock
+                    || id == 12 // sand
+                    || id == 13 // gravel
+                    // hell
+                    || id == 87 // netherstone
+                    || id == 88 // slowsand
+                    || id == 89 // lightstone
+                    // ores
+                    || id == 14 // coal ore
+                    || id == 15 // iron ore
+                    || id == 16 // gold ore
+                    || id == 56 // diamond ore
+                    || id == 73 // redstone ore
+                    || id == 74 // redstone ore (active)
+            ) {
+                return y;
+            }
+        }
+        return minY;
+    }
 }
diff --git a/src/HeightMap.java b/src/HeightMap.java
new file mode 100755
index 000000000..c9739c500
--- /dev/null
+++ b/src/HeightMap.java
@@ -0,0 +1,161 @@
+// $Id$
+/*
+ * WorldEditLibrary
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import com.sk89q.worldedit.MaxChangedBlocksException;
+import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.blocks.BaseBlock;
+import com.sk89q.worldedit.filters.HeightMapFilter;
+import com.sk89q.worldedit.regions.Region;
+
+/**
+ * Allows applications of Kernels onto the region's heightmap.
+ * Currently only used for smoothing (with a GaussianKernel).
+ * 
+ * @author Grum
+ */
+
+public class HeightMap {
+    private int[] data;
+    private int width;
+    private int height;
+
+    private Region region;
+    private EditSession session;
+
+    /**
+     * Constructs the HeightMap
+     * 
+     * @param session
+     * @param region
+     */
+
+    public HeightMap(EditSession session, Region region) {
+        this.session = session;
+        this.region = region;
+
+        this.width = region.getWidth();
+        this.height = region.getLength();
+
+        int minX = region.getMinimumPoint().getBlockX();
+        int minY = region.getMinimumPoint().getBlockY();
+        int minZ = region.getMinimumPoint().getBlockZ();
+        int maxY = region.getMaximumPoint().getBlockY();
+
+        // Store current heightmap data
+        data = new int[width * height];
+        for (int z = 0; z < height; z++) {
+            for (int x = 0; x < width; x++) {
+                data[z * width + x] = session.getHighestTerrainBlock(x + minX, z + minZ, minY, maxY);
+            }
+        }
+    }
+
+    /**
+     * Apply the filter 'iterations' amount times.
+     * 
+     * @param filter
+     * @param iterations
+     * @return number of blocks affected
+     * @throws MaxChangedBlocksException
+     */
+
+    public int applyFilter(HeightMapFilter filter, int iterations) throws MaxChangedBlocksException {
+        int[] newData = new int[data.length];
+        System.arraycopy(data, 0, newData, 0, data.length);
+
+        for (int i = 0; i < iterations; i++)
+            newData = filter.filter(newData, width, height);
+
+        return apply(newData);
+    }
+
+    /**
+     * Apply a raw heightmap to the region
+     * 
+     * @param data
+     * @return number of blocks affected
+     * @throws MaxChangedBlocksException
+     */
+
+    public int apply(int[] data) throws MaxChangedBlocksException {
+        Vector minY = region.getMinimumPoint();
+        int originX = minY.getBlockX();
+        int originY = minY.getBlockY();
+        int originZ = minY.getBlockZ();
+
+        int maxY = region.getMaximumPoint().getBlockY();
+        BaseBlock fillerAir = new BaseBlock(0);
+
+        int blocksChanged = 0;
+
+        // Apply heightmap
+        for (int z = 0; z < height; z++) {
+            for (int x = 0; x < width; x++) {
+                int index = z * width + x;
+                int curHeight = this.data[index];
+
+                // Clamp newHeight within the selection area
+                int newHeight = Math.min(maxY, data[index]);
+
+                // Offset x,z to be 'real' coordinates
+                int X = x + originX;
+                int Z = z + originZ;
+
+                // We are keeping the topmost blocks so take that in account for the scale
+                double scale = (double) (curHeight - originY) / (double) (newHeight - originY);
+
+                // Depending on growing or shrinking we need to start at the bottom or top
+                if (newHeight > curHeight) {
+                    // Set the top block of the column to be the same type (this might go wrong with rounding)
+                    session.setBlock(new Vector(X, newHeight, Z), session.getBlock(new Vector(X, curHeight, Z)));
+                    blocksChanged++;
+
+                    // Grow -- start from 1 below top replacing airblocks
+                    for (int y = newHeight - 1 - originY; y >= 0; y--) {
+                        int copyFrom = (int) (y * scale);
+                        session.setBlock(new Vector(X, originY + y, Z), session.getBlock(new Vector(X, originY + copyFrom, Z)));
+                        blocksChanged++;
+                    }
+                } else if (curHeight > newHeight) {
+                    // Shrink -- start from bottom
+                    for (int y = 0; y < newHeight - originY; y++) {
+                        int copyFrom = (int) (y * scale);
+                        session.setBlock(new Vector(X, originY + y, Z), session.getBlock(new Vector(X, originY + copyFrom, Z)));
+                        blocksChanged++;
+                    }
+
+                    // Set the top block of the column to be the same type
+                    // (this could otherwise go wrong with rounding)
+                    session.setBlock(new Vector(X, newHeight, Z), session.getBlock(new Vector(X, curHeight, Z)));
+                    blocksChanged++;
+
+                    // Fill rest with air
+                    for (int y = newHeight + 1; y <= curHeight; y++) {
+                        session.setBlock(new Vector(X, y, Z), fillerAir);
+                        blocksChanged++;
+                    }
+                }
+            }
+        }
+
+        // Drop trees to the floor -- TODO
+
+        return blocksChanged;
+    }
+}
diff --git a/src/WorldEditListener.java b/src/WorldEditListener.java
old mode 100644
new mode 100755
index b1df1b60c..697e0b15e
--- a/src/WorldEditListener.java
+++ b/src/WorldEditListener.java
@@ -31,6 +31,7 @@ import java.io.*;
 import com.sk89q.worldedit.*;
 import com.sk89q.worldedit.blocks.*;
 import com.sk89q.worldedit.data.*;
+import com.sk89q.worldedit.filters.*;
 import com.sk89q.worldedit.snapshots.*;
 import com.sk89q.worldedit.regions.*;
 import com.sk89q.worldedit.patterns.*;
@@ -165,6 +166,7 @@ public class WorldEditListener extends PluginListener {
         commands.put("/butcher", "<Radius> - Kill nearby mobs");
         commands.put("//use", "[SnapshotID] - Use a particular snapshot");
         commands.put("//restore", "<SnapshotID> - Restore a particular snapshot");
+        commands.put("//smooth", "<Iterations> <Sigma> - Smooth an area's heightmap");
     }
 
     /**
@@ -937,6 +939,21 @@ public class WorldEditListener extends PluginListener {
 
             return true;
 
+        // Smooth the heightmap of a region
+        } else if (split[0].equalsIgnoreCase("//smooth")) {
+            checkArgs(split, 0, 1, split[0]);
+
+            int iterations = 1;
+            if (split.length >= 2)
+                iterations = Integer.parseInt(split[1]);
+
+            HeightMap heightMap = new HeightMap(editSession, session.getRegion());
+            HeightMapFilter filter = new HeightMapFilter(new GaussianKernel(5, 1.0));
+            int affected = heightMap.applyFilter(filter, iterations);
+            player.print("Terrain's heightmap has been smoothed. " + affected + " block(s) have been changed.");
+
+            return true;
+
         // Set the outline of a region
         } else if(split[0].equalsIgnoreCase("//outline")) {
             checkArgs(split, 1, 1, split[0]);
diff --git a/src/com/sk89q/worldedit/filters/GaussianKernel.java b/src/com/sk89q/worldedit/filters/GaussianKernel.java
new file mode 100755
index 000000000..4241f8b95
--- /dev/null
+++ b/src/com/sk89q/worldedit/filters/GaussianKernel.java
@@ -0,0 +1,57 @@
+// $Id$
+/*
+ * WorldEditLibrary
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.filters;
+
+import java.awt.image.Kernel;
+
+/**
+ * A Gaussian Kernel generator (2D bellcurve)
+ * 
+ * @author Grum
+ */
+
+public class GaussianKernel extends Kernel {
+    
+    /**
+     * Constructor of the kernel
+     * 
+     * @param radius the resulting diameter will be radius * 2 + 1
+     * @param sigma controls 'flatness'
+     */
+
+    public GaussianKernel(int radius, double sigma) {
+        super(radius * 2 + 1, radius * 2 + 1, createKernel(radius, sigma));
+    }
+
+    private static float[] createKernel(int radius, double sigma) {
+        int diameter = radius * 2 + 1;
+        float[] data = new float[diameter*diameter];
+
+        double sigma22 = 2 * sigma * sigma;
+        double constant = Math.PI * sigma22;
+        for (int y = -radius; y <= radius; y++) {
+            for (int x = -radius; x <= radius; x++) {
+                data[(y+radius) * diameter + x+radius] = (float) (Math.exp(-(x * x + y * y) / sigma22) / constant);
+            }
+        }
+
+        return data;
+    }
+}
diff --git a/src/com/sk89q/worldedit/filters/HeightMapFilter.java b/src/com/sk89q/worldedit/filters/HeightMapFilter.java
new file mode 100755
index 000000000..124dab288
--- /dev/null
+++ b/src/com/sk89q/worldedit/filters/HeightMapFilter.java
@@ -0,0 +1,118 @@
+// $Id$
+/*
+ * WorldEditLibrary
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.filters;
+
+import java.awt.image.Kernel;
+
+/**
+ * Allows applications of Kernels onto the region's heightmap.
+ * Only used for smoothing (with a GaussianKernel).
+ * 
+ * @author Grum
+ */
+
+public class HeightMapFilter {
+    private Kernel kernel;
+
+    /**
+     * Construct the HeightMapFilter object.
+     * 
+     * @param kernel
+     */
+    public HeightMapFilter(Kernel kernel) {
+        this.kernel = kernel;
+    }
+
+    /**
+     * Construct the HeightMapFilter object.
+     * 
+     * @param kernelWidth
+     * @param kernelHeight
+     * @param kernelData
+     */
+    public HeightMapFilter(int kernelWidth, int kernelHeight, float[] kernelData) {
+        this.kernel = new Kernel(kernelWidth, kernelHeight, kernelData);
+    }
+
+    /**
+     * @return the kernel
+     */
+    public Kernel getKernel() {
+        return kernel;
+    }
+
+    /**
+     * Set Kernel
+     * 
+     * @param kernel
+     */
+    public void setKernel(Kernel kernel) {
+        this.kernel = kernel;
+    }
+
+    /**
+     * Filter with a 2D kernel
+     * 
+     * @param inData
+     * @param width
+     * @param height
+     * @return the modified heightmap
+     */
+    public int[] filter(int[] inData, int width, int height ) {
+        int index = 0;
+        float[] matrix = kernel.getKernelData(null);
+        int[] outData = new int[inData.length];
+
+        int kh = kernel.getHeight();
+        int kw = kernel.getWidth();
+        int kox = kernel.getXOrigin();
+        int koy = kernel.getYOrigin();
+        
+        for (int y = 0; y < height; y++) {
+            for (int x = 0; x < width; x++) {
+                float z = 0;
+
+                for (int ky = 0; ky < kh; ky++) {
+                    int offsetY = y + ky - koy;
+                    // Clamp coordinates inside data
+                    if (offsetY < 0 || offsetY >= height)
+                        offsetY = y;
+                    
+                    offsetY *= width;
+
+                    int matrixOffset = ky * kw;
+                    for (int kx = 0; kx < kw; kx++) {
+                        float f = matrix[matrixOffset + kx];
+                        if (f == 0) continue;
+
+                        int offsetX = x + kx - kox;
+                        // Clamp coordinates inside data
+                        if (offsetX < 0 || offsetX >= width)
+                                offsetX = x;
+ 
+                        z += f * inData[offsetY + offsetX];
+                    }
+                }
+                outData[index++] = (int) (z + 0.5);
+            }
+        }
+        return outData;
+    }
+}
diff --git a/src/com/sk89q/worldedit/filters/LinearKernel.java b/src/com/sk89q/worldedit/filters/LinearKernel.java
new file mode 100755
index 000000000..021514b61
--- /dev/null
+++ b/src/com/sk89q/worldedit/filters/LinearKernel.java
@@ -0,0 +1,44 @@
+// $Id$
+/*
+ * WorldEditLibrary
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.filters;
+
+import java.awt.image.Kernel;
+
+/**
+ * A linear Kernel generator (all cells weight the same)
+ * 
+ * @author Grum
+ */
+
+public class LinearKernel extends Kernel {
+
+    public LinearKernel(int radius) {
+        super(radius * 2 + 1, radius * 2 + 1, createKernel(radius));
+    }
+
+    private static float[] createKernel(int radius) {
+        int diameter = radius * 2 + 1;
+        float[] data = new float[diameter*diameter];
+        
+        for (int i = 0; i < data.length; data[i++] = 1.0f/data.length) ;
+
+        return data;
+    }
+}