This operator returns the current ray-bounce level.
For example, primary rays (i.e. rays sent from the camera) are level 0. After a single reflection, the ray level is 1. After two reflections, the level is 2, etc.
Note: The pbrlighting function used in the default surface model may not actually perform recursive ray-tracing, so the bounce level may not ever exceed one. Please look at the rayimport VOP.