I'm using PhysX 3.1 as my game's physics engine. One requirement is that I need set different density for each shape(there are server shapes for my single rigid actor). I know that the shape's density can be set by NxShapeDesc::density in PhysX 2.8, but I can't find such interface in PhysX 3.1. I know that the mass properties can be set in PhysX 3.1 just as the snowman example in the SDK, but I don't know whether there exists a direct interface to set density for each shape.