diff --git a/Demos/CharacterDemo/DynamicCharacterController.cpp b/Demos/CharacterDemo/DynamicCharacterController.cpp
index abea84eb9..ce8ed96ef 100644
--- a/Demos/CharacterDemo/DynamicCharacterController.cpp
+++ b/Demos/CharacterDemo/DynamicCharacterController.cpp
@@ -33,7 +33,7 @@ void DynamicCharacterController::setup (btScalar height, btScalar width, btScala
 
 	m_halfHeight = height/btScalar(2.0);
 
-	m_shape = new btMultiSphereShape (btVector3(width/btScalar(2.0), height/btScalar(2.0), width/btScalar(2.0)), &spherePositions[0], &sphereRadii[0], 2);
+	m_shape = new btMultiSphereShape (&spherePositions[0], &sphereRadii[0], 2);
 
 	btTransform startTransform;
 	startTransform.setIdentity ();
diff --git a/src/BulletCollision/CollisionShapes/btMultiSphereShape.cpp b/src/BulletCollision/CollisionShapes/btMultiSphereShape.cpp
index 7788f2d9c..baebfb092 100644
--- a/src/BulletCollision/CollisionShapes/btMultiSphereShape.cpp
+++ b/src/BulletCollision/CollisionShapes/btMultiSphereShape.cpp
@@ -19,8 +19,8 @@ subject to the following restrictions:
 #include "BulletCollision/CollisionShapes/btCollisionMargin.h"
 #include "LinearMath/btQuaternion.h"
 
-btMultiSphereShape::btMultiSphereShape (const btVector3& inertiaHalfExtents,const btVector3* positions,const btScalar* radi,int numSpheres)
-:btConvexInternalAabbCachingShape (), m_inertiaHalfExtents(inertiaHalfExtents)
+btMultiSphereShape::btMultiSphereShape (const btVector3* positions,const btScalar* radi,int numSpheres)
+:btConvexInternalAabbCachingShape ()
 {
 	m_shapeType = MULTI_SPHERE_SHAPE_PROXYTYPE;
 	btScalar startMargin = btScalar(BT_LARGE_FLOAT);
@@ -38,8 +38,6 @@ btMultiSphereShape::btMultiSphereShape (const btVector3& inertiaHalfExtents,cons
 
 }
 
-
-
  
  btVector3	btMultiSphereShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0)const
 {
@@ -125,27 +123,17 @@ void	btMultiSphereShape::calculateLocalInertia(btScalar mass,btVector3& inertia)
 {
 	//as an approximation, take the inertia of the box that bounds the spheres
 
-	btTransform ident;
-	ident.setIdentity();
-//	btVector3 aabbMin,aabbMax;
+	btVector3 localAabbMin,localAabbMax;
+	getCachedLocalAabb(localAabbMin,localAabbMax);
+	btVector3 halfExtents = (localAabbMax-localAabbMin)*btScalar(0.5);
 
-//	getAabb(ident,aabbMin,aabbMax);
+	btScalar lx=btScalar(2.)*(halfExtents.x());
+	btScalar ly=btScalar(2.)*(halfExtents.y());
+	btScalar lz=btScalar(2.)*(halfExtents.z());
 
-	btVector3 halfExtents = m_inertiaHalfExtents;//(aabbMax - aabbMin)* btScalar(0.5);
-
-	btScalar margin = CONVEX_DISTANCE_MARGIN;
-
-	btScalar lx=btScalar(2.)*(halfExtents[0]+margin);
-	btScalar ly=btScalar(2.)*(halfExtents[1]+margin);
-	btScalar lz=btScalar(2.)*(halfExtents[2]+margin);
-	const btScalar x2 = lx*lx;
-	const btScalar y2 = ly*ly;
-	const btScalar z2 = lz*lz;
-	const btScalar scaledmass = mass * btScalar(.08333333);
-
-	inertia[0] = scaledmass * (y2+z2);
-	inertia[1] = scaledmass * (x2+z2);
-	inertia[2] = scaledmass * (x2+y2);
+	inertia.setValue(mass/(btScalar(12.0)) * (ly*ly + lz*lz),
+					mass/(btScalar(12.0)) * (lx*lx + lz*lz),
+					mass/(btScalar(12.0)) * (lx*lx + ly*ly));
 
 }
 
diff --git a/src/BulletCollision/CollisionShapes/btMultiSphereShape.h b/src/BulletCollision/CollisionShapes/btMultiSphereShape.h
index ae8e5c26f..f1c4cbf34 100644
--- a/src/BulletCollision/CollisionShapes/btMultiSphereShape.h
+++ b/src/BulletCollision/CollisionShapes/btMultiSphereShape.h
@@ -22,21 +22,15 @@ subject to the following restrictions:
 #include "LinearMath/btAabbUtil2.h"
 
 ///The btMultiSphereShape represents the convex hull of a collection of spheres. You can create special capsules or other smooth volumes.
-///It is possible to animate the spheres for deformation.
+///It is possible to animate the spheres for deformation, but call 'recalcLocalAabb' after changing any sphere position/radius
 class btMultiSphereShape : public btConvexInternalAabbCachingShape
-
 {
 	
-
-
 	btAlignedObjectArray<btVector3> m_localPositionArray;
 	btAlignedObjectArray<btScalar>  m_radiArray;
-	btVector3	m_inertiaHalfExtents;
-
-
-
+	
 public:
-	btMultiSphereShape (const btVector3& inertiaHalfExtents,const btVector3* positions,const btScalar* radi,int numSpheres);
+	btMultiSphereShape (const btVector3* positions,const btScalar* radi,int numSpheres);
 
 	///CollisionShape Interface
 	virtual void	calculateLocalInertia(btScalar mass,btVector3& inertia) const;
diff --git a/src/BulletDynamics/Dynamics/Bullet-C-API.cpp b/src/BulletDynamics/Dynamics/Bullet-C-API.cpp
index 56026bf39..32b63f195 100644
--- a/src/BulletDynamics/Dynamics/Bullet-C-API.cpp
+++ b/src/BulletDynamics/Dynamics/Bullet-C-API.cpp
@@ -181,12 +181,12 @@ plCollisionShapeHandle plNewBoxShape(plReal x, plReal y, plReal z)
 plCollisionShapeHandle plNewCapsuleShape(plReal radius, plReal height)
 {
 	//capsule is convex hull of 2 spheres, so use btMultiSphereShape
-	btVector3 inertiaHalfExtents(radius,height,radius);
+	
 	const int numSpheres = 2;
 	btVector3 positions[numSpheres] = {btVector3(0,height,0),btVector3(0,-height,0)};
 	btScalar radi[numSpheres] = {radius,radius};
 	void* mem = btAlignedAlloc(sizeof(btMultiSphereShape),16);
-	return (plCollisionShapeHandle) new (mem)btMultiSphereShape(inertiaHalfExtents,positions,radi,numSpheres);
+	return (plCollisionShapeHandle) new (mem)btMultiSphereShape(positions,radi,numSpheres);
 }
 plCollisionShapeHandle plNewConeShape(plReal radius, plReal height)
 {