Option to Auto Set LC number of passes

[mmaitland]

In our studio we do a lot of Fly-through Light Cache / Irradiance Map animations and I understand that for Light Cache, the number of passes should not exceed the number of CPU threads because this will introduce noise. If this this is true, would it be possible to have an option for the number of passes to automatically be set to the number of CPU threads? We need this because our farm has some computers with 8 threads and others with 24.
Thanks,
Matt

[vlado]

This is done already; since V-Ray 2.0 you can set the number of passes to 0 - in that case, V-Ray will automatically choose a suitable value based on the number of rendering threads.

Best regards,
Vlado

[mmaitland]

Thank you Vlado!

[bardo]

vlado..and for a DR job, every machine renders LC passes at his best or using 0 to passes the main machine force the slaves at his LC passes value??

[vlado]

vlado..and for a DR job, every machine renders LC passes at his best or using 0 to passes the main machine force the slaves at his LC passes value??

For the moment, each machine will determine the number of passes independently from the rest, which may lead to differences in the GI solution. If you think that passing the value from the main machine might work better - we can certainly look into it.

Best regards,
Vlado

[bardo]

Vlado: it was only to understand how it works now.
From my experience, at the moment, I'm not sure what is better, but thinking of it I feel is better to have less differences in GI as much as possible but to have the "right" number the DR should evaluate all the different CPU and use the lowest number.

[MoonDoggie]

^ But lead to slowed down calculations. Maybe the new VRay installer will have two options: Conservative Mode, and Ultra-Hi-Tech super mode.

[vlado]

Actually we can just take the max value from all machines. This will not affect the calculations on the slower machines (there is no problem if the passes are > the number of threads) but will make sure fast machines are fully used.

Best regadrs,
Vlado

[bardo]

It's solved!

Go for "Ultra-Hi-Tech super mode".

But mmaitland wrote "...I understand that for Light Cache, the number of passes should not exceed the number of CPU threads because this will introduce noise...", vlado do you confirm?? From your last reply it seems it isn't right ...but you know Vray best of all of us...

[vlado]

Well, the light cache samples will be slightly noiser, this is true - but in most cases this doesn't matter too much.

Best regards,
Vlado

[MoonDoggie]

Awesome, thanks for the clarification Vlado.

[mmaitland]

It would be pretty nice if when I am using DR, the fastest computer to come up with a LC solution "wins" and sends the solution onto the other computers. On my workstation, I have 12 CPU threads but a lot of the renderfarm has 24 CPU threads, and often the servers are waiting for my workstation to finish.
Thanks!

Matt Maitland
Senior 3D Designer
Teague