what is the purpose of PxCapsuleControllerDesc.material about physx

[PierreTerdiman]

This is just the material assigned to the underlying kinematic actor. This is mostly here because the SDK expects a material for a shape, but this is indeed not used by the CCT module, as least for the behavior of characters.

[haolly]

@PierreTerdiman maybe it was used when CCT does not move? e.g. when another CCT collide with this no-moving CCT? Because only CCT's move method take a PxControllerFilters parameter

[PierreTerdiman]

CCTs are kinematic so this wouldn't be used either when CCTs collide. However I think you're right that the material parameters will be used when e.g. a dynamic rigid body collides with a non-moving CCT. In this case the material's parameters will affect the behavior of that rigid body.