An instance mask which affects ray-instance masking during ray tracing on the GPU.
Typically, each ray tracing effect can use a dedicated RayTracingInstanceCullingTest configuration and different instanceMask value.
If the test passes, the instanceMask value will be ORed into a final 8-bit ray tracing instance mask. When casting rays on the GPU using TraceRay HLSL function, the instanceInclusionMask argument of TraceRay is ANDed with the final 8-bit instance mask to include or reject ray tracing instances during acceleration structure traversal.