Hello,

So I’ve been trying to alter the number of cores through a macro by using “SYSP 901, []”. However, each time I run the ray trace (NSTR 1, 0, 0, 0, 0, 0, 0), the number of cores resets to its maximum value.

To attempt to identify why, I re-used the code proposed HERE, adding a “print SYPR(901)”, and I get the following.

The elapsed time varies somewhat, but stays close enough to one another to conclude that the NSTR is somehow resetting the # of core before running the ray trace.

-The duration is coherent with 20 cores (~7.8s) if I run it using the Ray Trace Control window; the time at 1 core is ~40s, 16 cores 7.4 s

-I’ve tried using the advanced options in the system explorer to Turn Off Threading, without it having any apparent effect.

-Apparently NSTR does an update to everything before running, but I’ve not been able to reproduce the bug with “UPDATE” so I don't think that's the cause.

-I’ve tried other files and seen the same issue (namely Projector Modeled Using an IES Data File.ZDA from the samples).

Any ideas as to the cause? I might have missed something in the help, as the related terms (Threads, Core and CPU) are used almost interchangeably and there might be a term I’ve not seen.