Setting Thread Count

Currently there are four ways to set the number of render threads in RfK, in order of precedence:

1. The preferences interactiveRenderThreadsOverride and interactiveRenderThreads3D (equivalent to the use of the "--threads3d" command line parameter in batch mode). If you want to definitively set the number of render threads this will be the place to do it.
2. The attribute renderSettings.renderThreads (via AttributeSet, it is not exposed in RenderSettings)
3. PrmanGlobalSettings: commandArguments.numThreadModeProcs
4. PrmanGlobalSettings: options.limits.threads. This translates literally to RIB: Option "limits" "int threads" [N]

The first three will trigger a "-t:#" addition to the command line arguments for prman which, by RenderMan definition, will override any thread specification in the RIB.

Special Values

If a value of 0 (zero) is given to prman via either the "-t" command line or the "threads" option then all CPUs will be utilized for rendering. If a negative value (-N) is specified then prman will use all but N CPUs for rendering.