As the name suggests, minRelief is an implementation of relief mapping for mental ray and RenderMan. This shader simulates the effects of displacement mapping without actually affecting the model.
In our tests the shading model was about 2-3x faster than rendering true displacements in high quality settings with very little visual disparity. Moreover, there’s no need to apply surface approximation nodes to your models for this shader to do its work.
Usage
We use minRelief in situations where displacement mapping is overkill but simple bump or normal mapping doesn’t provide enough depth.
