Intersecting Volume Grids still not working in Vray Next GPU / Vray 5 unstable

[trainofthought]

Hi there,

Some serious issues which are effecting my production: Volume Grid clouds have hard line intersecting issues when rendering on GPU/CUDA - see image attached. Issue not present when rendering on CPU, but this is not an option for me as the render is 10 times slower. This issue is most prominent around frame 280 in the attached Maya scene file (zipped)

I've also had to downgrade to Vray 4.3 as stability issues were becoming unbearable with Vray 5 / Maya 2018.5 - literally a full bomb out crash every few minutes while IPR rendering. Downgrading made the scene stable again, so it must be Vray 5 - I did the uninstall / install process twice to be sure. I did check and the intersection issue is also present when rendering in Vray 5.

Please help!

[hermit.crab]

Thanks for the report. We are aware of the issue (internal bug-tracker id: PHI-3509); our developers are looking into it. As a workaround, make sure there aren't overlapping VolumeGrid walls (try moving the grids a bit). Regarding the stability - the viewport and IPR responsiveness do seem slower, though it hasn't crashed on my end. I'll notify the development team about this.

EDIT: This is not a bug, but a current GPU limitation. No more than 4 volumes that overlap at the same position in space can be rendered. We'll try to improve this.

[trainofthought]

Cheers Alexs,

OK, that limitation makes sense as I didn't see the problem everywhere, only when I had a certain amount of the volumes. As I'm trying to make a dense bank of clouds in my scene, they really do need to overlap a fair amount for the desired look. The GPU limit is a pity as it's quite impossible for me to render this scene with CPU due to the slowness compared to GPU. Hopefully this can be improved in future versions!

[eXeCuze]

Yeah i am having the same issue as well. (thanks for pointing me to this thread Hermit.Crab) Now i at least know that i have to avoid more then 4 overlapping volumes, which shouldn't be such a big problem on my scene. Still would be great to get a fix for this of course

[eXeCuze]

Any update on this? Its a pretty annoying bug, was really hoping for a quick fix / temporary solution to the problem?

[hermit.crab]

Any update on this? Its a pretty annoying bug, was really hoping for a quick fix / temporary solution to the problem?

Not quite yet, I'm afraid. It is a limitation, not a bug., hence resolving it would require more time due to the complexity of the matter.

[paxilon]

Hi,

is there already a solution or workaround? As you can see the intersecting bounding box is visible as a bright line and intersecting Volumes still not work with GPU. (I am using FastSSS Mat on the Mountains)

[hermit.crab]

Hi,

is there already a solution or workaround? As you can see the intersecting bounding box is visible as a bright line and intersecting Volumes still not work with GPU. (I am using FastSSS Mat on the Mountains)

Not quite yet, I'm afraid. I'll add your report to the log as well. Rendering in CPU may be the only workaround.