IR maps use 50% cpu power?

[digitalx3d]

I've noticed many times that when our renderfarm is rendering irradiance maps, the cpus are running between 50-70%. And it seems like this more than doubles the frame times. Shouldn't they be at 100%? Any ideas how to fix this?

Also, sometimes when the farm is rendering the actual raytraced frames, I see the cpus not going to the full 100%. Usually deleting the max.ini file solves this problem and then it renders at 100% again. But then soon after it slows back down, and you have to keep repeating this. Any thoughts?

John Pruden
Digital-X

[vlado]

Maybe the multithreading option in 3dsmax turns off for some reason? If this is case, you can try to hard-code the number of threads that V-Ray uses by typing in maxscript listener:

renderers.current.system_numThreads=2

Then V-Ray will always use two threads (or whatever else you want) no matter what is the 3dsmax multithreading option.

Best regards,
Vlado

[vergefio]

Mhh, interesting... Vlado i have 4 thread, if i type:

renderers.current.system_numThreads=8

will vray split those 4 in 8? Or simply still uses 4 threads?

[vlado]

Mhh, interesting... Vlado i have 4 thread, if i type:

renderers.current.system_numThreads=8

will vray split those 4 in 8? Or simply still uses 4 threads?

V-Ray will use whatever number you type. If you type 128, it will use 128 threads and you will have 128 buckets at the same time (granted, with this many threads, a lot of time is spent switching between them instead of doing actual work). The default value for this hidden parameter is 0, which means that V-Ray will use as many threads as there are processors.

Best regards,
Vlado

[throb]

V-Ray will use whatever number you type. If you type 128, it will use 128 threads and you will have 128 buckets at the same time (granted, with this many threads, a lot of time is spent switching between them instead of doing actual work). The default value for this hidden parameter is 0, which means that V-Ray will use as many threads as there are processors.

i found that turning off hyperthreading and using the regular old 2 cpus actually resulted in the same rendertime but i could actually use my machine for something else (checking email, etc) while the vray render went. I have heard of hyperthreading creating enough overhead to make hardcore processing go slower than with single threads....
interesting...

[panthon]

As a test, you could disable vray displacement and see if you still get that 50% cpu usage. I´ve run into similar problems several times and it seemed to be related to vraydisplacement, creating lots of geometry which forced vray to load/unload a huge amount of RAM thus slowing the render.

[RErender]

Might be interesting to try http://forums.splutterfish.com/viewt...0fc77f152b2145