Hello, I have been reading the documentation for UDK about physical materials and masks. I have my 1bit BMP mask, and the two physical material assets I want to shoot off in the black and white channels. I have applied my material to both a rigid body and to a skeletal mesh and neither apparently uses the mask. If I assign a regular physical material (one that doesn't use a mask) then it will work fine, but this defeats the point because it gives only one hit reaction. In the documentation it states that it is possible to extend a class on which we want to use a physical material based on the KActor class's usage. How to do that? Here is the quote: "The following properties [ie, ImpactEffect - Particle system to spawn at the point of impact + ImpactSound - Sound to play when an impact occurs] allow you to attach sounds and effects to physical collisions. These only work on classes which support them, which at the moment is only KActor. By looking at the implementation in KActor though, you can add this functionality to other classes (or you can subclass KActor)." Essentially, how to make sure a PhysicalMaterial mask actually works? What code could be added to a skeletal mesh class perhaps, to get it going? Any help appreciated.