diff --git a/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.cpp b/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.cpp
index 991841ee2..286e6c31f 100644
--- a/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.cpp
+++ b/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.cpp
@@ -229,6 +229,7 @@ void btCompoundCollisionAlgorithm::processCollision (const btCollisionObjectWrap
 		removeChildAlgorithms();
 		
 		preallocateChildAlgorithms(body0Wrap,body1Wrap);
+		m_compoundShapeRevision = compoundShape->getUpdateRevision();
 	}
 
 
diff --git a/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.h b/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.h
index 536751456..7d792c18d 100644
--- a/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.h
+++ b/src/BulletCollision/CollisionDispatch/btCompoundCollisionAlgorithm.h
@@ -36,6 +36,7 @@ extern btShapePairCallback gCompoundChildShapePairCallback;
 /// btCompoundCollisionAlgorithm  supports collision between CompoundCollisionShapes and other collision shapes
 class btCompoundCollisionAlgorithm  : public btActivatingCollisionAlgorithm
 {
+protected:
 	btAlignedObjectArray<btCollisionAlgorithm*> m_childCollisionAlgorithms;
 	bool m_isSwapped;
 
diff --git a/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.cpp b/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.cpp
index 3f5c08e61..b0103fc8c 100644
--- a/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.cpp
+++ b/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.cpp
@@ -27,10 +27,8 @@ subject to the following restrictions:
 btShapePairCallback gCompoundCompoundChildShapePairCallback = 0;
 
 btCompoundCompoundCollisionAlgorithm::btCompoundCompoundCollisionAlgorithm( const btCollisionAlgorithmConstructionInfo& ci,const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap,bool isSwapped)
-:btActivatingCollisionAlgorithm(ci,body0Wrap,body1Wrap),
-m_sharedManifold(ci.m_manifold)
+:btCompoundCollisionAlgorithm(ci,body0Wrap,body1Wrap,isSwapped)
 {
-	m_ownsManifold = false;
 
 	void* ptr = btAlignedAlloc(sizeof(btHashedSimplePairCache),16);
 	m_childCollisionAlgorithmCache= new(ptr) btHashedSimplePairCache();
@@ -292,12 +290,21 @@ void btCompoundCompoundCollisionAlgorithm::processCollision (const btCollisionOb
 	const btCompoundShape* compoundShape0 = static_cast<const btCompoundShape*>(col0ObjWrap->getCollisionShape());
 	const btCompoundShape* compoundShape1 = static_cast<const btCompoundShape*>(col1ObjWrap->getCollisionShape());
 
+	const btDbvt* tree0 = compoundShape0->getDynamicAabbTree();
+	const btDbvt* tree1 = compoundShape1->getDynamicAabbTree();
+	if (!tree0 || !tree1)
+	{
+		return btCompoundCollisionAlgorithm::processCollision(body0Wrap,body1Wrap,dispatchInfo,resultOut);
+	}
 	///btCompoundShape might have changed:
 	////make sure the internal child collision algorithm caches are still valid
 	if ((compoundShape0->getUpdateRevision() != m_compoundShapeRevision0) || (compoundShape1->getUpdateRevision() != m_compoundShapeRevision1))
 	{
 		///clear all
 		removeChildAlgorithms();
+		m_compoundShapeRevision0 = compoundShape0->getUpdateRevision();
+		m_compoundShapeRevision1 = compoundShape1->getUpdateRevision();
+
 	}
 
 
@@ -329,8 +336,7 @@ void btCompoundCompoundCollisionAlgorithm::processCollision (const btCollisionOb
 	}
 
 
-	const btDbvt* tree0 = compoundShape0->getDynamicAabbTree();
-	const btDbvt* tree1 = compoundShape1->getDynamicAabbTree();
+	
 
 	btCompoundCompoundLeafCallback callback(col0ObjWrap,col1ObjWrap,this->m_dispatcher,dispatchInfo,resultOut,this->m_childCollisionAlgorithmCache,m_sharedManifold);
 
diff --git a/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.h b/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.h
index 8aba3919d..5fe3fc443 100644
--- a/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.h
+++ b/src/BulletCollision/CollisionDispatch/btCompoundCompoundCollisionAlgorithm.h
@@ -17,6 +17,8 @@ subject to the following restrictions:
 #ifndef BT_COMPOUND_COMPOUND_COLLISION_ALGORITHM_H
 #define BT_COMPOUND_COMPOUND_COLLISION_ALGORITHM_H
 
+#include "btCompoundCollisionAlgorithm.h"
+
 #include "BulletCollision/CollisionDispatch/btActivatingCollisionAlgorithm.h"
 #include "BulletCollision/BroadphaseCollision/btDispatcher.h"
 #include "BulletCollision/BroadphaseCollision/btBroadphaseInterface.h"
@@ -35,15 +37,12 @@ typedef bool (*btShapePairCallback)(const btCollisionShape* pShape0, const btCol
 extern btShapePairCallback gCompoundCompoundChildShapePairCallback;
 
 /// btCompoundCompoundCollisionAlgorithm  supports collision between two btCompoundCollisionShape shapes
-class btCompoundCompoundCollisionAlgorithm  : public btActivatingCollisionAlgorithm
+class btCompoundCompoundCollisionAlgorithm  : public btCompoundCollisionAlgorithm
 {
 
 	class btHashedSimplePairCache*	m_childCollisionAlgorithmCache;
 	btSimplePairArray m_removePairs;
 
-	class btPersistentManifold*	m_sharedManifold;
-	bool					m_ownsManifold;
-
 
 	int	m_compoundShapeRevision0;//to keep track of changes, so that childAlgorithm array can be updated
 	int	m_compoundShapeRevision1;