diff --git a/include/SurfaceExtractors.h b/include/SurfaceExtractors.h
index 251ce977..ead8f2cc 100644
--- a/include/SurfaceExtractors.h
+++ b/include/SurfaceExtractors.h
@@ -30,7 +30,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 namespace PolyVox
 {
-	void generateRoughMeshDataForRegion(BlockVolume<boost::uint8_t>* volumeData, boost::uint16_t regionX, boost::uint16_t regionY, boost::uint16_t regionZ, IndexedSurfacePatch* singleMaterialPatch, IndexedSurfacePatch* multiMaterialPatch);
+	void generateRoughMeshDataForRegion(BlockVolume<boost::uint8_t>* volumeData, Region region, IndexedSurfacePatch* singleMaterialPatch, IndexedSurfacePatch* multiMaterialPatch);
 	Vector3DFloat computeNormal(BlockVolume<boost::uint8_t>* volumeData, const Vector3DFloat& position, NormalGenerationMethod normalGenerationMethod);
 
 	void generateSmoothMeshDataForRegion(BlockVolume<boost::uint8_t>* volumeData, boost::uint16_t regionX, boost::uint16_t regionY, boost::uint16_t regionZ, IndexedSurfacePatch* singleMaterialPatch, IndexedSurfacePatch* multiMaterialPatch);
diff --git a/source/SurfaceExtractors.cpp b/source/SurfaceExtractors.cpp
index e4b0ebe3..22adcc72 100644
--- a/source/SurfaceExtractors.cpp
+++ b/source/SurfaceExtractors.cpp
@@ -4,21 +4,27 @@
 #include "GradientEstimators.h"
 #include "IndexedSurfacePatch.h"
 #include "MarchingCubesTables.h"
+#include "Region.h"
 #include "VolumeIterator.h"
 
 using namespace boost;
 
 namespace PolyVox
 {
-	void generateRoughMeshDataForRegion(BlockVolume<uint8_t>* volumeData, uint16_t regionX, uint16_t regionY, uint16_t regionZ, IndexedSurfacePatch* singleMaterialPatch, IndexedSurfacePatch* multiMaterialPatch)
+	void generateRoughMeshDataForRegion(BlockVolume<uint8_t>* volumeData, Region region, IndexedSurfacePatch* singleMaterialPatch, IndexedSurfacePatch* multiMaterialPatch)
 	{	
-		//First and last voxels in the region
-		const uint16_t firstX = regionX * POLYVOX_REGION_SIDE_LENGTH;
-		const uint16_t firstY = regionY * POLYVOX_REGION_SIDE_LENGTH;
-		const uint16_t firstZ = regionZ * POLYVOX_REGION_SIDE_LENGTH;
-		const uint16_t lastX = (std::min)(firstX + POLYVOX_REGION_SIDE_LENGTH-1,volumeData->getSideLength()-2);
-		const uint16_t lastY = (std::min)(firstY + POLYVOX_REGION_SIDE_LENGTH-1,volumeData->getSideLength()-2);
-		const uint16_t lastZ = (std::min)(firstZ + POLYVOX_REGION_SIDE_LENGTH-1,volumeData->getSideLength()-2);
+		//When generating the mesh for a region we actually look one voxel outside it in the
+		// back, bottom, right direction. Protect against access violations by cropping region here
+		Region regVolume = volumeData->getEnclosingRegion();
+		regVolume.setUpperCorner(regVolume.getUpperCorner() - Vector3DInt32(1,1,1));
+		region.cropTo(regVolume);
+
+		const uint16_t firstX = region.getLowerCorner().x();
+		const uint16_t firstY = region.getLowerCorner().y();
+		const uint16_t firstZ = region.getLowerCorner().z();
+		const uint16_t lastX = region.getUpperCorner().x();
+		const uint16_t lastY = region.getUpperCorner().y();
+		const uint16_t lastZ = region.getUpperCorner().z();
 
 		//Offset from lower block corner
 		const Vector3DFloat offset(firstX,firstY,firstZ);
diff --git a/source/VolumeChangeTracker.cpp b/source/VolumeChangeTracker.cpp
index 849163bd..f5f164a8 100644
--- a/source/VolumeChangeTracker.cpp
+++ b/source/VolumeChangeTracker.cpp
@@ -83,7 +83,14 @@ namespace PolyVox
 						regionGeometry.m_patchMultiMaterial = new IndexedSurfacePatch(true);
 						regionGeometry.m_v3dRegionPosition = Vector3DInt32(regionX, regionY, regionZ);
 
-						generateRoughMeshDataForRegion(volumeData, regionX,regionY,regionZ, regionGeometry.m_patchSingleMaterial, regionGeometry.m_patchMultiMaterial);
+						const uint16_t firstX = regionX * POLYVOX_REGION_SIDE_LENGTH;
+						const uint16_t firstY = regionY * POLYVOX_REGION_SIDE_LENGTH;
+						const uint16_t firstZ = regionZ * POLYVOX_REGION_SIDE_LENGTH;
+						const uint16_t lastX = firstX + POLYVOX_REGION_SIDE_LENGTH-1;
+						const uint16_t lastY = firstY + POLYVOX_REGION_SIDE_LENGTH-1;
+						const uint16_t lastZ = firstZ + POLYVOX_REGION_SIDE_LENGTH-1;
+
+						generateRoughMeshDataForRegion(volumeData, Region(Vector3DInt32(firstX, firstY, firstZ), Vector3DInt32(lastX, lastY, lastZ)), regionGeometry.m_patchSingleMaterial, regionGeometry.m_patchMultiMaterial);
 
 						regionGeometry.m_bContainsSingleMaterialPatch = regionGeometry.m_patchSingleMaterial->getVertices().size() > 0;
 						regionGeometry.m_bContainsMultiMaterialPatch = regionGeometry.m_patchMultiMaterial->getVertices().size() > 0;