[HOU-3578] Adaptive Bucket splitting broken?

[doppelgaengerdigital]

I have a scene in H.19.5.403 and the latest Vray5 nightly and a Volume Grid.

Adaptive Bucket Splitting is working until it doesn't. The last 2 or 3 splits it loses cores it seems and the CPU load goes down. The remaining cores split, but losing cores goes on.
When rendering without the volume it works fine.

[Gosho.Genchev]

Hey doppelgaengerdigital ,

Thanks for the heads up! Is there anything in particular (meaning non-default) with the Volume Shader in your scene that I should watch out for? Would it be possible for you to give us a demo scene, or at least a screen shot of your volume shader settings?

Best regards!

[doppelgaengerdigital]

Hello!

Here is a link to the cache and the Vray setup. I am rendering in LOPS.
https://www.dropbox.com/t/RCJnIjZ2UKsedXTE

Thanks for investigation!

[doppelgaengerdigital]

Gosho.Genchev

I started a thread over here ( https://forums.chaos.com/forum/v-ray...023-and-vray-6 )
to discuss performance differences with Volume Grids between Maya and Houdini.
I did some testing and boiled it down to the Probabilistic Volumes setting in Houdini and Maya.

This setting seems to be ignored in Houdini, even if enabled, which causes increased rendertime and failing adaptive bucket splitting.
I have the same setup in Maya and Houdini with a Volume Grid and simple Lights. Rendered in Maya with Probabilistic Volumes enabled is super fast and takes ~14sec.
When I disable Probabilistic Volumes in Maya the Rendertime goes up to ~100s and the adaptive Bucket splitting is also broken.

In Houdini the same scene takes ~120s and the adaptive bucket splitting is broken, no matter if the Probabilistic Volumes are enabled or disabled.. (Which is discussed here: https://forums.chaos.com/forum/v-ray...litting-broken )

See attached Screenshots.

Hopefully this helps and you can fix this for the upcoming nightlies.

[Gosho.Genchev]

Hey doppelgaengerdigital ,

First of all - thank you for tracking this down! You're absolutely correct - it looks like the probabilistic settings are ignored for GUI rendering.
I've logged a ticket for our dev team and we'll resolve this ASAP.

Best regards!