[HOU-4765] Nothing is being rendered on GPU with motion blur turned on

[Mokiki]

It seems like in solaris when motion blur on the GPU is turned on nothing is being rendered.
This does not happen outside of Solaris.

Currently using Houdini 20.5.455
and vray 7 build-22920
GPU: 3090
Drivers Tested: 572.83 & 572.70
OS: Windows 11

I recorded a small video to show the problem:

[Gosho.Genchev]

Hey Mokiki,

Thank you for the heads up - we're looking into it! I'll get back to you when we know more.

Best regards!

[Mokiki]

Thanks for letting me know. Hopefully it's something that's easily resolvable.

[Mokiki]

I know you guys are busy but is there any new information regarding this potential bug?

[Gosho.Genchev]

Hey Mokiki ,

The QA folks haven't reached the ticket and tested yet - there is a fix in the nightly builds as of yesterday.

Best regards!

[Mokiki]

Maybe there is a typo cause I am slightly confused.
QA didn't reach the ticket yet but there is a fix in the nightly builds as of yesterday?
Nonetheless I did download the newest vray 7 for houdini nightly to test it out and the issue is still there.

[Mokiki]

Nevermind apparently after a pc reboot it is fixed. Sometimes the mesh still disappears but restarting the render or changing the current frame a couple of times seems to bring it back.

[bdancer]

> Sometimes the mesh still disappears

This should not happen, same scene?
I've just downloaded the latest nightly and the fix is there indeed.
Sure you've used nightly build (and not stable nightly which is not yet updated)?

[Mokiki]

bdancer

Yup same scene. It mostly happened right after loading up the scene. Have the mesh not appear at all but after either Changing the frame, turning on and off the motion blur setting, changing the shutter speed and restarting the render. Once the mesh loaded up once with motion blur visible it'll work consistently from there.
Which is why my initial previous post before the last one assumed the issue was still there until rebooting my pc and playing around with the settings.

Maybe it was the kernel needing be created again?

I am currently using this build:

V-Ray for Houdini number:22929 hash:ed94f58 from 15 Apr 2025 01:53
V-Ray Core 7.00.12 [a5520c44] from 11 Apr 2025

[bdancer]

> Maybe it was the kernel needing be created again?

It's recompiled automatically, restart is not needed.

> Yup same scene... Have the mesh not appear at all but after either Changing the frame...

Well, I can't reproduce any of this, hopefuly QAs will be able to reproduce this...

[Mokiki]

bdancer
I'll also keep an eye on it and see if I can figure out the steps to replicate it consistently.
Will post if I find anything out on my end.

[bdancer]

> Will post if I find anything out on my end.

Thanks a lot!