How do I render VDBs from Bifrost Graph to Arnold (GPU)? "[gpu] could not create bifrost_multires_volume"

[Polytikal1]

I have been using bifrost graph editors to pull in VDBs, and have not been able to figure out how to render with GPUs. I continue to get errors that bifrost graph is multi res volume is not recognized by GPU. Any workarounds or pointers would help. 

If anyone knows, can you just give me a yes or no, or tutorial link. I'd appreciate it. It'll take a couple of minutes to share.

[morten.bojsen-hansen]

At the time of this writing Arnold GPU does not render Bifrost volumes (neither fog volumes nor level sets). Also, Arnold CPU does not render Bifrost level sets. We are actively working on rectifying these limitations although I cannot provide a timeline at this point.

[Polytikal1]

So bifrost can create an aero sim, but it cannot read and render vdb’s via gpu? Not even a single channel? An article would be good at some point because there are contradicting options (a couple) online via forum statements. And, On the Arnold settings volume node, there’s a level set option, what would that be for? 

[Polytikal1]

If VDBs can be rendered by Arnold gpu outside of bifrost, but not from a graph, then it could be a bifrost issue. I’ve reached out via Arnold forum to see whether past comments are true that Arnold gpu has been rendering vdb volumes. 

[Stephen.Blair]

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@Polytikal1 wrote:

If VDBs can be rendered by Arnold gpu outside of bifrost, but not from a graph, then it could be a bifrost issue. I’ve reached out via Arnold forum to see whether past comments are true that Arnold gpu has been rendering vdb volumes. 

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Arnold renders VDB on GPU

[Polytikal1]

Thank for confirming! Any idea as to how to troubleshoot the error message I’m receiving, which indicates that gpu is unable to render multi resolution volume from graph output? Arnold comes with nanoVDB I read, and I have the updated gpu drivers for 3090Ti’s, so I’m a bit lost… 

the result of the error is a blue Arnold render view of any vdbs read out from bifrost graph that I have in the scene.

[morten.bojsen-hansen]

@Polytikal1 Please read my message again. Bifrost graph does not output VDB volumes. It outputs Bifrost volumes (which is what Arnold calls multi resolution volumes).

[Polytikal1]

I see… so if that bifrost shapes with read VDB were animated, would the only workaround be to try to Re target the shape’s animation to a VDB read via Maya? 

[morten.bojsen-hansen]

If you insist on rendering with Arnold GPU then you need to cache to VDB for now. Otherwise Arnold CPU still works fine. Arnold can render VDB files without Maya though.