PhysX Shape doen't collide when Hull type is set to Mesh

[Ajayshenoy]

PhysX Shape doesn't collide when Hull type is set to Mesh in the PhysX Shape Operator. It works fine with Convex Hull and other hull types, but when I set it to Mesh it falls into abyss without colliding. 

But, PhysX Collision Operator works well with all Hull types, including mesh. Is there something I am missing? Thanks in advance.