V-Ray 5 VRayVolumeGrid cannot read RGB channel from .AUR cache created in PhoenixFD 5.

[dennis_michel]

I am having a problem using PhoenixFD 5 with VRay 5. I previously created an explosion using PhoenixFD 4 and saving RGB channel into .AUR cache. I simulate another explosion using the same .max file but this time using PhoenixFD 5 instead of 4. And there is a problem. VRay 5 VRayVolumeGrid cannot see RGB channel saved with PhoenixFD 5 .AUR cache. If I load .AUR cache into VRayVolumeGrid in VRay 6 then everything looks fine. Is there a way to fix RGB channel in VRay 5 created in PhoenixFD 5?
This is a duplicated post from V-Ray thread because I am not sure if this is VRay or PhoenixFD issue. https://forums.chaos.com/node/1168598

[Svetlin.Nikolov]

Hey, could you try the latest stable nightly of V-Ray 5? I recently picked some changes to the AUR format there...
https://nightlies.chaos.com/#/vrayma...e_5.2/20221220

Cheers!

[dennis_michel]

Hey, could you try the latest stable nightly of V-Ray 5? I recently picked some changes to the AUR format there...
https://nightlies.chaos.com/#/vrayma...e_5.2/20221220

Cheers!

I am downloading and will let you know later. Thank you! Does this mean that I need to make simulation again to create AUR cache files with latest Phoenix build?

[Svetlin.Nikolov]

Ah, no no, you shouldn't need to simulate again. Just try loading the caches in the volume grid

[dennis_michel]

Ah, no no, you shouldn't need to simulate again. Just try loading the caches in the volume grid

I have installed the latest build but it doesn't help. I still see the grid without RGB channel.

[Svetlin.Nikolov]

Ah, could you attach one such aur cache so I can check it? It could be the smallest one in size, just as long as it has RGB in it.

[dennis_michel]

All files are big, so I share it via Dropbox. https://www.dropbox.com/s/6v9xnx3vqj..._0036.aur?dl=0

[Svetlin.Nikolov]

Thank you, got it! Let's see...

[Svetlin.Nikolov]

Hmm, so I installed nightly 31805, created a brand new VolumeGrid, loaded the cache and the RGB showed up in the viewport.

I added a V-Ray sun, turned off the Fire in the volume grid and set the Smoke Color to RGB and it rendered correctly. Does it work the same for you if you do the same steps as me?

[dennis_michel]

What VRay version do you use? I have VDB as black in viewport in VRay 5/

[dennis_michel]

Oh, I missed that you show VRay version on your screenshot. Could you investigate my .max file with PhoenixFDFire and VRayVolumeGrid side by side, please? (Attached) I use VRay version 5.20.23 build 00001. Are there any changes between my version and yours that might have effect?

[Svetlin.Nikolov]

Checking it right now, thanks!

[Svetlin.Nikolov]

Oh no, 5.20.23 won't do for this cache - you need the stable nightly build I sent you. With 5.20.23 it's black for me as well, while with the stable nightly both Phoenix and the VolumeGrid render correctly.

Btw, just a warning - in this scene I don't see any issues, but overlapping Phoenix and VolumeGrid containers could have them rendered wrong - most probably one of them would appear entirely in front or behind the other. In order to get proper blending between overlapping containers, it's best to have them all as either Phoenix Simulators, or VolumeGrids.

[dennis_michel]

I have updated to phoenixFD_adv_50102_max2022_vray5_x64_31809 and vray_adv_52024_max2022_x64_31805 and tried to render file Phoenix_Explosion_v02_002.max I provided early. It doesn't render at all. I get just a black frame without alpha. What is more dangerous, after I tried to render this file and got black frame, I made 3ds Max reset to the new file. I tried to render empty scene and got 3ds Max crash. I repeated this a couple of times just to confirm this is not a random crash. After that I restarted 3ds Max and merged VRayVolumeGrid from Phoenix_Explosion_v02_002.max and it renders fine. So, I can say that everything works fine now, but I am afraid that I will have a problem with older 3ds max project files in case I will need to re-render them.
Thank you for your warning about overlapping Phoenix and VolumeGrid containers. I didn't know about that. I usually do not use them together but this is good to know.

[Svetlin.Nikolov]

Huh, let me try the nightly. I tested your scene with the official Phoenix 5.01 and the 31805 stable nightly and it worked correctly, then rolled the vray version back to the official vray that you tried - 5.20.23 and it rendered black. Let me try the vray stable nightly and the phoenix nightly now...