[HOU-2437] VDB delayed load

[pablo_rohtau]

Hello is it possible to load VDBs at render time and not include them in the vrscene archives?
If it is possible, since we work on windows but render on linux, will vray convert the paths in the vrscene to Posix?
Thanks

[glacierise]

Delayed load volumes - set the file node to packed disk primitive mode. The auto change of paths - we're relying on Deadline to do this for us, check your render manager options.

[pablo_rohtau]

Thanks glacierise !
I tried using Packed Disc Prims, and yes is rendering fine but I think that when you export to vrscene is still putting the VDB data inside.
I got this message in the logs for all my objects that renders volumes:

Failed to find/use volume path for "/obj/smoke_render_vray" because of "/obj/smoke_render_vray/OUT", writing data directly

If you use packed disc prims in Mantra your IFDs are minimal, the pack prim only holds the actual geometry path, is doing like an implicit delayed load. Looks to me like is not doing the same thing in vray.
Or I'm missing something

[david.anastacio]

Thanks glacierise !
I tried using Packed Disc Prims, and yes is rendering fine but I think that when you export to vrscene is still putting the VDB data inside.
I got this message in the logs for all my objects that renders volumes:

Failed to find/use volume path for "/obj/smoke_render_vray" because of "/obj/smoke_render_vray/OUT", writing data directly

If you use packed disc prims in Mantra your IFDs are minimal, the pack prim only holds the actual geometry path, is doing like an implicit delayed load. Looks to me like is not doing the same thing in vray.
Or I'm missing something

Hi,

See this threads:
https://forums.chaosgroup.com/forum/...port-with-vdbs
https://forums.chaosgroup.com/forum/...67#post1101467

Best,
David.

[pablo_rohtau]

Thanks David.
In my case the vrscenes are still "big", I think the volume is baked into them.
If I am correct in one of that threads you put before, you mentioned that the VDBs weren't baked in the vrscene, as expected of you are using packed disc prims, am I correct?
So that means, that apart from the slowness exporting and the RAM issues you managed so successfully delayed load your VDBs?

[glacierise]

Yes it should work, and the vrscene should only contain a pointer to the vdb file. Are you doing something after the file sop that might be unpacking?

[david.anastacio]

Thanks David.
In my case the vrscenes are still "big", I think the volume is baked into them.
If I am correct in one of that threads you put before, you mentioned that the VDBs weren't baked in the vrscene, as expected of you are using packed disc prims, am I correct?
So that means, that apart from the slowness exporting and the RAM issues you managed so successfully delayed load your VDBs?

Hey,

Yes, like glacierise said, there should be no issues with using VDBs, they are always just links in the vrscenes, unless your are unpacking.
Make sure that in the file SOP you set it to "Packed Disk Primitive", usualy this guys is the culprit, no matter if it's V-Ray or Mantra, as it defaults to load "All Geometry" which is unpacked data.



The "slowness" of the vrscene generation seems to be due to the bounding box of the volume being evaluated when the vrscene is getting generate (this should be fixed soon).

Best,
Daivd.

[pablo_rohtau]

Mmm not sure if this is working to be honest.
Using Packed Disk Primitive or All Geometry doesn't make any change in the file size of the vrscenes.
If I remove the volume from the render I have vrscenes of around 1MB, adding the volume they are around 25MB, the vrscene files are the same size no matter how I load the volume.
It is truth that the volume VDB is around 80MB and the vrscene is aroung 25MB so probably is applying and extra compression to it.
But as I said the size of the vrscenes are the same loading them as regular geometry and loading as Packed Disc Prims.

Cheers

[glacierise]

Open up the vrscene and see what's inside, it's s text file. Could point you in the right direction.

[pablo_rohtau]

Arrg, I'm idiot, I was caching the VDBs as bgeos, that was the reason!
Thanks guys, working now.

[glacierise]

Yeah don't beat yourself up, it happens It's a long road, setting all this up

[psanitra]

For WIN/LINUX paths you can use feature on the ROP export tab called Preserve Variables. Strings listed there will not be expanded on vrscene export.

For example,when you load your VDBs with file node you can set the path to something like ${MYPATH}/explosion.vdb, and set the Preserve variables to MYPATH.
Then all you need is MYPATH variable present on your OS and it will work.

[pablo_rohtau]

Thanks psanitra, that's good to know.