Starting in RenderMan 17.0, there is a new, optimized implementation of the curves primitive. However, there are a couple of known limitations with the new implementation:
- Re-rendering currently works with the new curves primitive implementation only when using the ray traced hider.
- The new, optimized curves primitive implementation is currently enabled for at most two motion samples.
If you see any problems with the new curves primitive implementation, it is possible to revert to the previous curves primitive implementation by setting an option (Option "hair" "int spatialgrouping" ), or by appending the following line to your rendermn.ini file (/prman/hair/spatialgrouping 0).