diff --git a/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.cpp b/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.cpp
new file mode 100644
index 000000000..20c0bc522
--- /dev/null
+++ b/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.cpp
@@ -0,0 +1,678 @@
+#include "btInternalEdgeUtility.h"
+
+#include "BulletCollision/CollisionShapes/btBvhTriangleMeshShape.h"
+#include "BulletCollision/CollisionShapes/btTriangleShape.h"
+#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
+#include "BulletCollision/NarrowPhaseCollision/btManifoldPoint.h"
+#include "LinearMath/btIDebugDraw.h"
+
+
+
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+//quick hack for debug drawing
+static btIDebugDraw* gDebugDrawer = 0;
+
+void	btSetDebugDrawer(btIDebugDraw* debugDrawer)
+{
+	gDebugDrawer = debugDrawer;
+}
+
+static void    btDebugDrawLine(const btVector3& from,const btVector3& to, const btVector3& color)
+{
+	if (gDebugDrawer)
+		gDebugDrawer->drawLine(from,to,color);
+}
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+
+static int	btGetHash(int partId, int triangleIndex)
+{
+	int hash = (partId<<(31-MAX_NUM_PARTS_IN_BITS)) | triangleIndex;
+	return hash;
+}
+
+
+
+static btScalar btGetAngle(const btVector3& edgeA, const btVector3& normalA,const btVector3& normalB)
+{
+	const btVector3 refAxis0  = edgeA;
+	const btVector3 refAxis1  = normalA;
+	const btVector3 swingAxis = normalB;
+	btScalar angle = btAtan2(swingAxis.dot(refAxis0), swingAxis.dot(refAxis1));
+	return  angle;
+}
+
+
+struct btConnectivityProcessor : public btTriangleCallback
+{
+	int				m_partIdA;
+	int				m_triangleIndexA;
+	btVector3*		m_triangleVerticesA;
+	btTriangleInfoMap*	m_triangleInfoMap;
+
+
+	virtual void processTriangle(btVector3* triangle, int partId, int triangleIndex)
+	{
+		//skip self-collisions
+		if ((m_partIdA == partId) && (m_triangleIndexA == triangleIndex))
+			return;
+
+		//skip duplicates (disabled for now)
+		//if ((m_partIdA <= partId) && (m_triangleIndexA <= triangleIndex))
+		//	return;
+
+		//search for shared vertices and edges
+		int numshared = 0;
+		int sharedVertsA[3]={-1,-1,-1};
+		int sharedVertsB[3]={-1,-1,-1};
+
+#if 0
+		printf("triangle A[0]	=	(%f,%f,%f)\ntriangle A[1]	=	(%f,%f,%f)\ntriangle A[2]	=	(%f,%f,%f)\n",
+			m_triangleVerticesA[0].getX(),m_triangleVerticesA[0].getY(),m_triangleVerticesA[0].getZ(),
+			m_triangleVerticesA[1].getX(),m_triangleVerticesA[1].getY(),m_triangleVerticesA[1].getZ(),
+			m_triangleVerticesA[2].getX(),m_triangleVerticesA[2].getY(),m_triangleVerticesA[2].getZ());
+
+		printf("partId=%d, triangleIndex=%d\n",partId,triangleIndex);
+		printf("triangle B[0]	=	(%f,%f,%f)\ntriangle B[1]	=	(%f,%f,%f)\ntriangle B[2]	=	(%f,%f,%f)\n",
+			triangle[0].getX(),triangle[0].getY(),triangle[0].getZ(),
+			triangle[1].getX(),triangle[1].getY(),triangle[1].getZ(),
+			triangle[2].getX(),triangle[2].getY(),triangle[2].getZ());
+#endif
+
+		for (int j=0;j<3;j++)
+		{
+			for (int i=0;i<3;i++)
+			{
+				if ( (m_triangleVerticesA[i]-triangle[j]).length2() < m_triangleInfoMap->m_equalVertexThreshold)
+				{
+					sharedVertsA[numshared] = i;
+					sharedVertsB[numshared] = j;
+					numshared++;
+				}
+			}
+		}
+		switch (numshared)
+		{
+		case 0:
+			{
+				break;
+			}
+		case 1:
+			{
+				//shared vertex
+				break;
+			}
+		case 2:
+			{
+				//shared edge
+				//we need to make sure the edge is in the order V2V0 and not V0V2 so that the signs are correct
+				if (sharedVertsA[0] == 0 && sharedVertsA[1] == 2)
+				{
+					sharedVertsA[0] = 2;
+					sharedVertsA[1] = 0;
+					int tmp = sharedVertsB[1];
+					sharedVertsB[1] = sharedVertsB[0];
+					sharedVertsB[0] = tmp;
+				}
+
+				int hash = btGetHash(m_partIdA,m_triangleIndexA);
+
+				btTriangleInfo* info = m_triangleInfoMap->find(hash);
+				if (!info)
+				{
+					btTriangleInfo tmp;
+					m_triangleInfoMap->insert(hash,tmp);
+					info = m_triangleInfoMap->find(hash);
+				}
+
+				int sumvertsA = sharedVertsA[0]+sharedVertsA[1];
+				int otherIndexA = 3-sumvertsA;
+
+				btVector3 edge(m_triangleVerticesA[sharedVertsA[1]]-m_triangleVerticesA[sharedVertsA[0]]);
+
+				btTriangleShape tA(m_triangleVerticesA[0],m_triangleVerticesA[1],m_triangleVerticesA[2]);
+				int otherIndexB = 3-(sharedVertsB[0]+sharedVertsB[1]);
+
+				btTriangleShape tB(triangle[sharedVertsB[1]],triangle[sharedVertsB[0]],triangle[otherIndexB]);
+				//btTriangleShape tB(triangle[0],triangle[1],triangle[2]);
+
+				btVector3 normalA;
+				btVector3 normalB;
+				tA.calcNormal(normalA);
+				tB.calcNormal(normalB);
+				edge.normalize();
+				btVector3 edgeCrossA = edge.cross(normalA).normalize();
+
+				{
+					btVector3 tmp = m_triangleVerticesA[otherIndexA]-m_triangleVerticesA[sharedVertsA[0]];
+					if (edgeCrossA.dot(tmp) < 0)
+					{
+						edgeCrossA*=-1;
+					}
+				}
+
+				btVector3 edgeCrossB = edge.cross(normalB).normalize();
+
+				{
+					btVector3 tmp = triangle[otherIndexB]-triangle[sharedVertsB[0]];
+					if (edgeCrossB.dot(tmp) < 0)
+					{
+						edgeCrossB*=-1;
+					}
+				}
+
+				btScalar	angle2 = 0;
+				btScalar	ang4 = 0.f;
+
+
+				btVector3 calculatedEdge = edgeCrossA.cross(edgeCrossB);
+				btScalar len2 = calculatedEdge.length2();
+
+				btScalar correctedAngle(0);
+				btVector3 calculatedNormalB = normalA;
+				bool isConvex = false;
+
+				if (len2<m_triangleInfoMap->m_planarEpsilon)
+				{
+					angle2 = 0.f;
+					ang4 = 0.f;
+				} else
+				{
+
+					calculatedEdge.normalize();
+					btVector3 calculatedNormalA = calculatedEdge.cross(edgeCrossA);
+					calculatedNormalA.normalize();
+					angle2 = btGetAngle(calculatedNormalA,edgeCrossA,edgeCrossB);
+					ang4 = SIMD_PI-angle2;
+					btScalar dotA = normalA.dot(edgeCrossB);
+					///@todo: check if we need some epsilon, due to floating point imprecision
+					isConvex = (dotA<0.);
+
+					correctedAngle = isConvex ? ang4 : -ang4;
+					btQuaternion orn2(calculatedEdge,-correctedAngle);
+					calculatedNormalB = btMatrix3x3(orn2)*normalA;
+
+
+				}
+
+				
+
+				
+							
+				//alternatively use 
+				//btVector3 calculatedNormalB2 = quatRotate(orn,normalA);
+
+
+				switch (sumvertsA)
+				{
+				case 1:
+					{
+						btVector3 edge = m_triangleVerticesA[0]-m_triangleVerticesA[1];
+						btQuaternion orn(edge,correctedAngle);
+						btVector3 computedNormalB = quatRotate(orn,normalA);
+						if (computedNormalB.dot(calculatedNormalB)<0)
+							info->m_flags |= TRI_INFO_V0V1_SWAP_NORMALB;
+
+						info->m_edgeV0V1Angle = correctedAngle;
+
+						if (isConvex)
+							info->m_flags |= TRI_INFO_V0V1_CONVEX;
+						break;
+					}
+				case 2:
+					{
+						btVector3 edge = m_triangleVerticesA[2]-m_triangleVerticesA[0];
+						btQuaternion orn(edge,correctedAngle);
+						btVector3 computedNormalB = quatRotate(orn,normalA);
+						if (computedNormalB.dot(calculatedNormalB)<0)
+							info->m_flags |= TRI_INFO_V2V0_SWAP_NORMALB;
+
+						info->m_edgeV2V0Angle = correctedAngle;
+						if (isConvex)
+							info->m_flags |= TRI_INFO_V2V0_CONVEX;
+						break;	
+					}
+				case 3:
+					{
+						btVector3 edge = m_triangleVerticesA[1]-m_triangleVerticesA[2];
+						btQuaternion orn(edge,correctedAngle);
+						btVector3 computedNormalB = quatRotate(orn,normalA);
+						if (computedNormalB.dot(calculatedNormalB)<0)
+							info->m_flags |= TRI_INFO_V1V2_SWAP_NORMALB;
+
+						info->m_edgeV1V2Angle = correctedAngle;
+
+						if (isConvex)
+							info->m_flags |= TRI_INFO_V1V2_CONVEX;
+						break;
+					}
+				}
+
+				break;
+			}
+		default:
+			{
+				//				printf("warning: duplicate triangle\n");
+			}
+
+		}
+	}
+};
+/////////////////////////////////////////////////////////
+/////////////////////////////////////////////////////////
+
+void btGenerateInternalEdgeInfo (btBvhTriangleMeshShape*trimeshShape, btTriangleInfoMap* triangleInfoMap)
+{
+	//the user pointer shouldn't already be used for other purposes, we intend to store connectivity info there!
+	if (trimeshShape->getUserPointer())
+		return;
+
+	trimeshShape->setUserPointer(triangleInfoMap);
+
+	btStridingMeshInterface* meshInterface = trimeshShape->getMeshInterface();
+	const btVector3& meshScaling = meshInterface->getScaling();
+
+	for (int partId = 0; partId< meshInterface->getNumSubParts();partId++)
+	{
+		const unsigned char *vertexbase = 0;
+		int numverts = 0;
+		PHY_ScalarType type = PHY_INTEGER;
+		int stride = 0;
+		const unsigned char *indexbase = 0;
+		int indexstride = 0;
+		int numfaces = 0;
+		PHY_ScalarType indicestype = PHY_INTEGER;
+		//PHY_ScalarType indexType=0;
+
+		btVector3 triangleVerts[3];
+		meshInterface->getLockedReadOnlyVertexIndexBase(&vertexbase,numverts,	type,stride,&indexbase,indexstride,numfaces,indicestype,partId);
+		btVector3 aabbMin,aabbMax;
+
+		for (int triangleIndex = 0 ; triangleIndex < numfaces;triangleIndex++)
+		{
+			unsigned int* gfxbase = (unsigned int*)(indexbase+triangleIndex*indexstride);
+
+			for (int j=2;j>=0;j--)
+			{
+
+				int graphicsindex = indicestype==PHY_SHORT?((unsigned short*)gfxbase)[j]:gfxbase[j];
+				if (type == PHY_FLOAT)
+				{
+					float* graphicsbase = (float*)(vertexbase+graphicsindex*stride);
+					triangleVerts[j] = btVector3(
+						graphicsbase[0]*meshScaling.getX(),
+						graphicsbase[1]*meshScaling.getY(),
+						graphicsbase[2]*meshScaling.getZ());
+				}
+				else
+				{
+					double* graphicsbase = (double*)(vertexbase+graphicsindex*stride);
+					triangleVerts[j] = btVector3( btScalar(graphicsbase[0]*meshScaling.getX()), btScalar(graphicsbase[1]*meshScaling.getY()), btScalar(graphicsbase[2]*meshScaling.getZ()));
+				}
+			}
+			aabbMin.setValue(btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT),btScalar(BT_LARGE_FLOAT));
+			aabbMax.setValue(btScalar(-BT_LARGE_FLOAT),btScalar(-BT_LARGE_FLOAT),btScalar(-BT_LARGE_FLOAT)); 
+			aabbMin.setMin(triangleVerts[0]);
+			aabbMax.setMax(triangleVerts[0]);
+			aabbMin.setMin(triangleVerts[1]);
+			aabbMax.setMax(triangleVerts[1]);
+			aabbMin.setMin(triangleVerts[2]);
+			aabbMax.setMax(triangleVerts[2]);
+
+			btConnectivityProcessor connectivityProcessor;
+			connectivityProcessor.m_partIdA = partId;
+			connectivityProcessor.m_triangleIndexA = triangleIndex;
+			connectivityProcessor.m_triangleVerticesA = &triangleVerts[0];
+			connectivityProcessor.m_triangleInfoMap  = triangleInfoMap;
+
+			trimeshShape->processAllTriangles(&connectivityProcessor,aabbMin,aabbMax);
+		}
+
+	}
+
+}
+
+
+
+
+// Given a point and a line segment (defined by two points), compute the closest point
+// in the line.  Cap the point at the endpoints of the line segment.
+void btNearestPointInLineSegment(const btVector3 &point, const btVector3& line0, const btVector3& line1, btVector3& nearestPoint)
+{
+	btVector3 lineDelta     = line1 - line0;
+
+	// Handle degenerate lines
+	if ( lineDelta.fuzzyZero())
+	{
+		nearestPoint = line0;
+	}
+	else
+	{
+		btScalar delta = (point-line0).dot(lineDelta) / (lineDelta).dot(lineDelta);
+
+		// Clamp the point to conform to the segment's endpoints
+		if ( delta < 0 )
+			delta = 0;
+		else if ( delta > 1 )
+			delta = 1;
+
+		nearestPoint = line0 + lineDelta*delta;
+	}
+}
+
+
+
+
+bool	btClampNormal(const btVector3& edge,const btVector3& tri_normal_org,const btVector3& localContactNormalOnB, btScalar correctedEdgeAngle, btVector3 & clampedLocalNormal)
+{
+	btVector3 tri_normal = tri_normal_org;
+	//we only have a local triangle normal, not a local contact normal -> only normal in world space...
+	//either compute the current angle all in local space, or all in world space
+
+	btVector3 edgeCross = edge.cross(tri_normal).normalize();
+	btScalar curAngle = btGetAngle(edgeCross,tri_normal,localContactNormalOnB);
+	{
+		if (curAngle < -correctedEdgeAngle)
+		{
+			btScalar diffAngle = correctedEdgeAngle-curAngle;
+			btQuaternion rotation(edge,diffAngle );
+			clampedLocalNormal = btMatrix3x3(rotation)*localContactNormalOnB;
+			return true;
+
+		} else
+		{
+			if (curAngle < correctedEdgeAngle)
+			{
+				//printf("angle within valid convex range, don't clamp it!\n");
+				return false;
+			} else
+			{
+				//			printf("too large angle\n");
+				btScalar diffAngle = correctedEdgeAngle-curAngle;
+
+				btQuaternion rotation(edge,diffAngle );
+				clampedLocalNormal = btMatrix3x3(rotation)*localContactNormalOnB;
+				//clamp it?
+				return true;
+			}
+		}
+	}
+	return false;
+}
+
+
+
+/// Changes a btManifoldPoint collision normal to the normal from the mesh.
+void btAdjustInternalEdgeContacts(btManifoldPoint& cp, const btCollisionObject* colObj0,const btCollisionObject* colObj1, int partId0, int index0)
+{
+
+	btAssert(colObj0->getCollisionShape()->getShapeType() == TRIANGLE_SHAPE_PROXYTYPE);
+	if (colObj0->getCollisionShape()->getShapeType() != TRIANGLE_SHAPE_PROXYTYPE)
+		return;
+
+	btTriangleInfoMap* triangleInfoMapPtr = (btTriangleInfoMap*) colObj0->getRootCollisionShape()->getUserPointer();
+	if (!triangleInfoMapPtr)
+		return;
+
+	int hash = btGetHash(partId0,index0);
+
+
+	btTriangleInfo* info = triangleInfoMapPtr->find(hash);
+	if (!info)
+		return;
+
+	const btTriangleShape* tri_shape = static_cast<const btTriangleShape*>(colObj0->getCollisionShape());
+	btVector3 v0,v1,v2;
+	tri_shape->getVertex(0,v0);
+	tri_shape->getVertex(1,v1);
+	tri_shape->getVertex(2,v2);
+
+	btVector3 center = (v0+v1+v2)*btScalar(1./3.);
+
+	btVector3 red(1,0,0), green(0,1,0),blue(0,0,1),white(1,1,1),black(0,0,0);
+	const btTransform& tr = colObj0->getWorldTransform();
+	btVector3 tri_normal;
+	tri_shape->calcNormal(tri_normal);
+
+	btScalar dot = tri_normal.dot(cp.m_normalWorldOnB);
+	btVector3 nearest;
+	btNearestPointInLineSegment(cp.m_localPointB,v0,v1,nearest);
+
+	btVector3 contact = cp.m_localPointB;
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+	btDebugDrawLine(tr*nearest,tr*cp.m_localPointB,red);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+
+
+	bool isNearEdge = false;
+
+	int numConcaveEdgeHits = 0;
+	int numConvexEdgeHits = 0;
+
+	btVector3 localContactNormalOnB = colObj0->getWorldTransform().getBasis().transpose() * cp.m_normalWorldOnB;
+	localContactNormalOnB.normalize();//is this necessary?
+
+	if ((info->m_edgeV0V1Angle)< SIMD_2_PI)
+	{
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+		btDebugDrawLine(tr*contact,tr*(contact+cp.m_normalWorldOnB*10),black);
+#endif
+		btScalar len = (contact-nearest).length();
+		if(len<triangleInfoMapPtr->m_edgeDistanceThreshold)
+		{
+			btVector3 edge(v0-v1);
+			isNearEdge = true;
+
+			if (info->m_edgeV0V1Angle==btScalar(0))
+			{
+				numConcaveEdgeHits++;
+			} else
+			{
+
+				bool isEdgeConvex = (info->m_flags & TRI_INFO_V0V1_CONVEX);
+				btScalar swapFactor = isEdgeConvex ? btScalar(1) : btScalar(-1);
+	#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+				btDebugDrawLine(tr*nearest,tr*(nearest+swapFactor*tri_normal*10),white);
+	#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+				btVector3 nA = swapFactor * tri_normal;
+
+				btQuaternion orn(edge,info->m_edgeV0V1Angle);
+				btVector3 computedNormalB = quatRotate(orn,tri_normal);
+				if (info->m_flags & TRI_INFO_V0V1_SWAP_NORMALB)
+					computedNormalB*=-1;
+				btVector3 nB = computedNormalB;
+
+				btScalar	NdotA = localContactNormalOnB.dot(nA);
+				btScalar	NdotB = localContactNormalOnB.dot(nB);
+				bool backFacingNormal = (NdotA< triangleInfoMapPtr->m_convexEpsilon) && (NdotB<triangleInfoMapPtr->m_convexEpsilon);
+
+				if (backFacingNormal)
+				{
+					numConcaveEdgeHits++;
+				}
+				else
+				{
+					numConvexEdgeHits++;
+					btVector3 clampedLocalNormal;
+					bool isClamped = btClampNormal(edge,swapFactor*tri_normal,localContactNormalOnB, swapFactor*info->m_edgeV0V1Angle,clampedLocalNormal);
+					if (isClamped)
+					{
+						btVector3 newNormal = colObj0->getWorldTransform().getBasis() * clampedLocalNormal;
+						//					cp.m_distance1 = cp.m_distance1 * newNormal.dot(cp.m_normalWorldOnB);
+						cp.m_normalWorldOnB = newNormal;
+						// Reproject collision point along normal. (what about cp.m_distance1?)
+						cp.m_positionWorldOnB = cp.m_positionWorldOnA - cp.m_normalWorldOnB * cp.m_distance1;
+						cp.m_localPointB = colObj0->getWorldTransform().invXform(cp.m_positionWorldOnB);
+					}
+				}
+			}
+		}
+	}
+
+	btNearestPointInLineSegment(contact,v1,v2,nearest);
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+	btDebugDrawLine(tr*nearest,tr*cp.m_localPointB,green);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+	if ((info->m_edgeV1V2Angle)< SIMD_2_PI)
+	{
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+		btDebugDrawLine(tr*contact,tr*(contact+cp.m_normalWorldOnB*10),black);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+
+
+		btScalar len = (contact-nearest).length();
+		if(len<triangleInfoMapPtr->m_edgeDistanceThreshold)
+		{
+			isNearEdge = true;
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+			btDebugDrawLine(tr*nearest,tr*(nearest+tri_normal*10),white);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+			btVector3 edge(v1-v2);
+
+			isNearEdge = true;
+
+			if (info->m_edgeV1V2Angle == btScalar(0))
+			{
+				numConcaveEdgeHits++;
+			} else
+			{
+				bool isEdgeConvex = (info->m_flags & TRI_INFO_V1V2_CONVEX)!=0;
+				btScalar swapFactor = isEdgeConvex ? btScalar(1) : btScalar(-1);
+	#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+				btDebugDrawLine(tr*nearest,tr*(nearest+swapFactor*tri_normal*10),white);
+	#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+				btVector3 nA = swapFactor * tri_normal;
+				
+				btQuaternion orn(edge,info->m_edgeV1V2Angle);
+				btVector3 computedNormalB = quatRotate(orn,tri_normal);
+				if (info->m_flags & TRI_INFO_V1V2_SWAP_NORMALB)
+					computedNormalB*=-1;
+				btVector3 nB = computedNormalB;
+
+				btScalar	NdotA = localContactNormalOnB.dot(nA);
+				btScalar	NdotB = localContactNormalOnB.dot(nB);
+				bool backFacingNormal = (NdotA< triangleInfoMapPtr->m_convexEpsilon) && (NdotB<triangleInfoMapPtr->m_convexEpsilon);
+
+				if (backFacingNormal)
+				{
+					numConcaveEdgeHits++;
+				}
+				else
+				{
+					numConvexEdgeHits++;
+					btVector3 localContactNormalOnB = colObj0->getWorldTransform().getBasis().transpose() * cp.m_normalWorldOnB;
+					btVector3 clampedLocalNormal;
+					bool isClamped = btClampNormal(edge,swapFactor*tri_normal,localContactNormalOnB, swapFactor*info->m_edgeV1V2Angle,clampedLocalNormal);
+					if (isClamped)
+					{
+						btVector3 newNormal = colObj0->getWorldTransform().getBasis() * clampedLocalNormal;
+						//					cp.m_distance1 = cp.m_distance1 * newNormal.dot(cp.m_normalWorldOnB);
+						cp.m_normalWorldOnB = newNormal;
+						// Reproject collision point along normal.
+						cp.m_positionWorldOnB = cp.m_positionWorldOnA - cp.m_normalWorldOnB * cp.m_distance1;
+						cp.m_localPointB = colObj0->getWorldTransform().invXform(cp.m_positionWorldOnB);
+					}
+				}
+			}
+		}
+	}
+
+	btNearestPointInLineSegment(contact,v2,v0,nearest);
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+	btDebugDrawLine(tr*nearest,tr*cp.m_localPointB,blue);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+	if ((info->m_edgeV2V0Angle)< SIMD_2_PI)
+	{
+
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+		btDebugDrawLine(tr*contact,tr*(contact+cp.m_normalWorldOnB*10),black);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+		btScalar len = (contact-nearest).length();
+		if(len<triangleInfoMapPtr->m_edgeDistanceThreshold)
+		{
+			isNearEdge = true;
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+			btDebugDrawLine(tr*nearest,tr*(nearest+tri_normal*10),white);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+			btVector3 edge(v2-v0);
+
+			if (info->m_edgeV2V0Angle==btScalar(0))
+			{
+				numConcaveEdgeHits++;
+			} else
+			{
+
+				bool isEdgeConvex = (info->m_flags & TRI_INFO_V2V0_CONVEX)!=0;
+				btScalar swapFactor = isEdgeConvex ? btScalar(1) : btScalar(-1);
+	#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+				btDebugDrawLine(tr*nearest,tr*(nearest+swapFactor*tri_normal*10),white);
+	#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+				btVector3 nA = swapFactor * tri_normal;
+				btQuaternion orn(edge,info->m_edgeV2V0Angle);
+				btVector3 computedNormalB = quatRotate(orn,tri_normal);
+				if (info->m_flags & TRI_INFO_V2V0_SWAP_NORMALB)
+					computedNormalB*=-1;
+				btVector3 nB = computedNormalB;
+
+				btScalar	NdotA = localContactNormalOnB.dot(nA);
+				btScalar	NdotB = localContactNormalOnB.dot(nB);
+				bool backFacingNormal = (NdotA< triangleInfoMapPtr->m_convexEpsilon) && (NdotB<triangleInfoMapPtr->m_convexEpsilon);
+
+				if (backFacingNormal)
+				{
+					numConcaveEdgeHits++;
+				}
+				else
+				{
+					numConvexEdgeHits++;
+					//				printf("hitting convex edge\n");
+
+
+					btVector3 localContactNormalOnB = colObj0->getWorldTransform().getBasis().transpose() * cp.m_normalWorldOnB;
+					btVector3 clampedLocalNormal;
+					bool isClamped = btClampNormal(edge,swapFactor*tri_normal,localContactNormalOnB,swapFactor* info->m_edgeV2V0Angle,clampedLocalNormal);
+					if (isClamped)
+					{
+						btVector3 newNormal = colObj0->getWorldTransform().getBasis() * clampedLocalNormal;
+						//					cp.m_distance1 = cp.m_distance1 * newNormal.dot(cp.m_normalWorldOnB);
+						cp.m_normalWorldOnB = newNormal;
+						// Reproject collision point along normal.
+						cp.m_positionWorldOnB = cp.m_positionWorldOnA - cp.m_normalWorldOnB * cp.m_distance1;
+						cp.m_localPointB = colObj0->getWorldTransform().invXform(cp.m_positionWorldOnB);
+					}
+				} 
+			}
+			
+
+		}
+	}
+
+
+	if (isNearEdge)
+	{
+
+		if (numConcaveEdgeHits>0)
+		{
+			//fix tri_normal so it pointing the same direction as the current local contact normal
+			if (tri_normal.dot(localContactNormalOnB) < 0)
+			{
+				tri_normal *= -1;
+			}
+			//for concave edge hits, just modify the normal to be the triangle normal
+			cp.m_normalWorldOnB = colObj0->getWorldTransform().getBasis() * tri_normal;
+			// Reproject collision point along normal.
+			cp.m_positionWorldOnB = cp.m_positionWorldOnA - cp.m_normalWorldOnB * cp.m_distance1;
+			cp.m_localPointB = colObj0->getWorldTransform().invXform(cp.m_positionWorldOnB);
+		}
+	}
+}
diff --git a/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.h b/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.h
new file mode 100644
index 000000000..733e83518
--- /dev/null
+++ b/src/BulletCollision/CollisionDispatch/btInternalEdgeUtility.h
@@ -0,0 +1,85 @@
+
+#ifndef BT_INTERNAL_EDGE_UTILITY_H
+#define BT_INTERNAL_EDGE_UTILITY_H
+
+#include <LinearMath/btHashMap.h>
+#include "LinearMath/btVector3.h"
+
+///The btInternalEdgeUtility helps to avoid or reduce artifacts due to wrong collision normals caused by internal edges.
+///See also http://code.google.com/p/bullet/issues/detail?id=27
+
+class btBvhTriangleMeshShape;
+class btCollisionObject;
+class btManifoldPoint;
+class btIDebugDraw;
+
+///for btTriangleInfo m_flags
+#define TRI_INFO_V0V1_CONVEX 1
+#define TRI_INFO_V1V2_CONVEX 2
+#define TRI_INFO_V2V0_CONVEX 4
+
+#define TRI_INFO_V0V1_SWAP_NORMALB 8
+#define TRI_INFO_V1V2_SWAP_NORMALB 16
+#define TRI_INFO_V2V0_SWAP_NORMALB 32
+
+
+///The btTriangleInfo structure stores information to adjust collision normals to avoid collisions against internal edges
+///it can be generated using 
+struct	btTriangleInfo
+{
+	btTriangleInfo()
+	{
+		m_edgeV0V1Angle = SIMD_2_PI;
+		m_edgeV1V2Angle = SIMD_2_PI;
+		m_edgeV2V0Angle = SIMD_2_PI;
+		m_flags=0;
+	}
+
+	int			m_flags;
+
+	btScalar	m_edgeV0V1Angle;
+	btScalar	m_edgeV1V2Angle;
+	btScalar	m_edgeV2V0Angle;
+
+};
+
+typedef btHashMap<btHashInt,btTriangleInfo> btInternalTriangleInfoMap;
+
+
+///The btTriangleInfoMap stores edge angle information for some triangles. You can compute this information yourself or using btGenerateInternalEdgeInfo.
+struct	btTriangleInfoMap : public btInternalTriangleInfoMap
+{
+	btScalar	m_convexEpsilon;///used to determine if an edge or contact normal is convex, using the dot product
+	btScalar	m_planarEpsilon; ///used to determine if a triangle edge is planar with zero angle
+	btScalar	m_equalVertexThreshold; ///used to compute connectivity: if the distance between two vertices is smaller than m_equalVertexThreshold, they are considered to be 'shared'
+	btScalar	m_edgeDistanceThreshold; ///used to determine edge contacts: if the closest distance between a contact point and an edge is smaller than this distance threshold it is considered to "hit the edge"
+	
+	btTriangleInfoMap()
+	{
+		m_convexEpsilon = 0.00f;
+		m_planarEpsilon = 0.0001f;
+		m_equalVertexThreshold = btScalar(0.0001)*btScalar(0.0001);
+		m_edgeDistanceThreshold = btScalar(0.1);
+	}
+};
+
+
+
+///Call btGenerateInternalEdgeInfo to create triangle info, store in the shape 'userInfo'
+void	btGenerateInternalEdgeInfo (btBvhTriangleMeshShape*trimeshShape, btTriangleInfoMap* triangleInfoMap);
+
+
+///Call the btFixMeshNormal to adjust the collision normal, using the triangle info map (generated using btGenerateInternalEdgeInfo)
+///If this info map is missing, or the triangle is not store in this map, nothing will be done
+void	btAdjustInternalEdgeContacts(btManifoldPoint& cp, const btCollisionObject* trimeshColObj0,const btCollisionObject* otherColObj1, int partId0, int index0);
+
+///Enable the BT_INTERNAL_EDGE_DEBUG_DRAW define and call btSetDebugDrawer, to get visual info to see if the internal edge utility works properly.
+///If the utility doesn't work properly, you might have to adjust the threshold values in btTriangleInfoMap
+#define BT_INTERNAL_EDGE_DEBUG_DRAW
+
+#ifdef BT_INTERNAL_EDGE_DEBUG_DRAW
+void	btSetDebugDrawer(btIDebugDraw* debugDrawer);
+#endif //BT_INTERNAL_EDGE_DEBUG_DRAW
+
+
+#endif //BT_INTERNAL_EDGE_UTILITY_H
\ No newline at end of file