Vray RT - Maya - GPU [CUDA] issues

[9k_JHT]

Hey all.

I'm running Maya 2016 with Vray 3.1 and I'm having some curious results when using Vray RT on my GPUs (non-SLI, 3x GTX 980 running up-to-date drivers).

First issue I'm having is that I believe that there is a disconnect of output between the 3 980 cards. I'm getting different colored (value) blocks around my entire scene that do not resolve over time. Almost like a banding effect. A link to a screen cast video below as well as a still image-




http://screencast.com/t/9YKn8kSSlgo

On top of this, there is a pretty stark difference between the results in color I'm getting from using the GPU (CUDA). The diffuse of these materials is driven by a gamma node (at .454, .454, .454), I don't know if this has anything to do with anything....






Anyone know any troubleshooting I can do? With results like this the GPU rendering isn't very useful for production or even for previz. I'd love to start using Vray RT with the GPU as it would be great if I could get it working correctly.

Thank you for any help,
Clayton

[savage309]

Hey,
Sorry for the troubles you have.
I can't think of any known issues that could cause that. It seems like pretty basic setup, but can you share the scene so we can check it in detail ? It would really help us.
Thanks,
Blago.

[9k_JHT]

Hey,
Sorry for the troubles you have.
I can't think of any known issues that could cause that. It seems like pretty basic setup, but can you share the scene so we can check it in detail ? It would really help us.
Thanks,
Blago.

Thank you for the reply. I'm excited to get this issue resolved since I bought 3 980 GTX cards solely for Vray RT.

Below is a link (weTransfer) of the archived scene-

http://we.tl/IRrlntgOpt

(http://we.tl/IRrlntgOpt)

Also, how does one get granted access to nightly builds of Vray? I think it would be neat to test any new functionality that you chaps come up with.

Best,
Clayton

[savage309]

When you start V-Ray RT GPU, a new process is spawned (it is a little console named V-Ray). Can you share what are the messages you get in the console ?
On first look it seems to work fine here, so it must be related to something with your setup. If the console messages do not help us to track that down, we can arrange online session with the help of our support team. So we can log on your machine and check what is not right - sometimes this is faster than going back and forth with more questions from our side.
For access to nightlies, you have to write to support@chaosgroup.com

[9k_JHT]

When you start V-Ray RT GPU, a new process is spawned (it is a little console named V-Ray). Can you share what are the messages you get in the console ?
On first look it seems to work fine here, so it must be related to something with your setup. If the console messages do not help us to track that down, we can arrange online session with the help of our support team. So we can log on your machine and check what is not right - sometimes this is faster than going back and forth with more questions from our side.
For access to nightlies, you have to write to support@chaosgroup.com

Below is the log (found here) "C:\Users\clayton.krause\AppData\Local\Temp\vraysl _log_20207.txt"

I could not attach it to this post (was told it exceeded size).



I'd be more than happy to setup a meeting with you guys as soon as possible to do some trouble shooting.


Thank you,
Clayton



LOG
----------------------
http://pastie.org/10478712

[savage309]

Okay, I will talk with the support guys to see when an online session could be arranged. I will try to make that happen as soon as possible.
I guess they will contact you either here or on your mail.

[tashko.zashev]

Hi Clayton,

Please send us an email to support@chaosgroup.com to arrange a time for remote connection. Don't forget to include a link to this thread in the mail.

Thank you.

[9k_JHT]

Hi Clayton,

Please send us an email to support@chaosgroup.com to arrange a time for remote connection. Don't forget to include a link to this thread in the mail.

Thank you.

Thanks much. I'll do that right away. Thank you for the help.

Best,
Clayton

[savage309]

Thanks much. I'll do that right away. Thank you for the help.

Best,
Clayton

Tashko managed to reproduce the issue.

Being able to reproduce it, I found what the problem is.
It is a corner case and happens only with gamma node, which has a flat color as input (will work with bitmap or noise for example) and multi GPU setup.
I have fixed that, it will take a couple of days before it gets into the nightlies. Will ping you when this happens. Sorry for the troubles.
And thanks a lot for the report.

[ricoholmes]

This is superb news for us too, thank you. Had noticed the effect was prevalent in older scenes of ours, but not so much newer. Older scenes were using a gamma adjust node with flat input a lot.
Again big thanks for the clarity and upcoming fix.

[9k_JHT]

Tashko managed to reproduce the issue.

Being able to reproduce it, I found what the problem is.
It is a corner case and happens only with gamma node, which has a flat color as input (will work with bitmap or noise for example) and multi GPU setup.
I have fixed that, it will take a couple of days before it gets into the nightlies. Will ping you when this happens. Sorry for the troubles.
And thanks a lot for the report.

Thank you for figuring this out! It was a curious case indeed. I'll get see about accessing those nightly builds.

Another unrelated issue that I was going to go over with support during our session was about the Vray switch material. I can make another thread in the correct area of the forums, but I keep on getting "// Warning: Unsupported texture VRaySwitchMtl //" messages in the Script editor. Is this a known issue (I don' t think it has affected the render output thus far, but it worries me)?

Best,
Clayton

Edit: I'm mentioning something to support in the reply email as will fyi.

[tashko.zashev]

Unfortunately we don't have support for V-Ray Switch material for RT / GPU yet. This is the reason why we print a warning about that in the log window.

I've replied to your ticket as well.

[9k_JHT]

Unfortunately we don't have support for V-Ray Switch material for RT / GPU yet. This is the reason why we print a working about that in the log window.

I've replied to your ticket as well.

I should of specified. The warning is firing when rendering off the Vray primary render engine, not just Vray RT. Thanks for the reply though. It's has been working, the warning just worried me as we are relying on the switch material heavily for production.

Thanks again.

Best,
Clayton

[tashko.zashev]

Would it be possible to send us your file to test it here?
You can start a new ticket about this issue by sending new mail to support@chaosgroup.com

Thank you.