(SOLVED)physx 3.3.0 bug in multi material mesh

There is a bug in 3.3.0 that cause my game crash randomly.every time I make a shape with this function:

createShape(pTriangleMeshGeometry, &physmaterials[0],numMaterial);

it cause random crashes in my game.My game is a racing game and it seems every time an object collide with two different part of mesh with different materials my game crash with no reason.I double checked my code and there is no error in it.unfortunately there is no sample in physx that uses multi material so I can’t be sure about it but I tested my code in 3.3.1 and it works but I have another problem in 3.3.1.You can see it here:

https://devtalk.nvidia.com/default/topic/768088/physx-and-physics-modeling/physx-3-3-1-collision-filter-bug/

I found the problem.It seems setting the inverse interia tensor of objects to zero was the cause of random crashes