private static void ApplyAnisotropicFriction(CollisionObject colObj, ref Vector3 frictionDirection)
		{
			if (colObj != null && colObj.HasAnisotropicFriction())
			{
				// transform to local coordinates
				Vector3 loc_lateral = MathUtil.TransposeTransformNormal(frictionDirection, colObj.GetWorldTransform());
				Vector3 friction_scaling = colObj.GetAnisotropicFriction();
				//apply anisotropic friction
				loc_lateral *= friction_scaling;
				// ... and transform it back to global coordinates
				frictionDirection = Vector3.TransformNormal(loc_lateral, colObj.GetWorldTransform());
			}
		}