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I never got the rendering speed out of VRay when rendering explisions with GI on surroundings that I am used to. I tried all kind of different parameters and tried to achieve render speed and predictable results of my output.
Most of the time I ended up with a lot of noise from GI or stuck buckets on refraction parts in my scene.
The following are the settings I ended up with and got super fast renderings.
Physically Based vs Artistic Flames
First thing I noticed was, that my overly bright flames came from the Physically Based Setting in the Fire Tab of my Volume Grid.
When I turn this setting down to 0 and go for an artistic approach, I can crank up the Fire multiplier to get the brightness I want out of my flames, and also the illumination I want.
This gives me the brightness I was expecting out of my flames. (I used a explosion simulation from the new Bifrost Graph)
Volume Light Cache vs Probabilistic volumetrics
So I read over in the VRay for Houdini Forums that I should completely deactivate the Volume Light Cache and use the Probabilistic Volumetrics Option in VRay Render settings Overrides under Volumetics Tab instead.
Immidiately my render speed increased and RAM usage went down 30%. Using this setup got rid of my stuck buckets and rendered nicely all over my scene.
Furthermore the Volume Light Cache setting produced too much noise on many of my explosions.
Fire Lights, Ray-Traced Smoke Color
I can even turn off Create Fire Lights and switch Smoke Color to Ray-Traced (GI Only). I am getting constant, fast, predictable renderings without any stuck buckets or too much noise.
Light Cache GI vs Brute Force GI
There is even pretty much no speed difference when switching from Light Cache over to Brute Force, wich was not possible before.
Those settings are fast to setup without having to trial an error and render super fast. At least for me and for now, so there is no guarantee that those settings arte best for everything and for everyone.
Imho the VRay documentation and the Volume Grid Shader settings have to be updated soon.
They discussed this topic in here also:
https://forums.chaosgroup.com/forum/...cache-concerns
https://forums.chaosgroup.com/forum/...tion-fireflies
Testrendering 58 Frames 600x600px, Min Subdivs 1, Max 12, Threshold 0.02
6min on Threadripper 3970x
https://we.tl/t-VGwNoEAfsJ
1200x1200px, Min subdivs 1, Max 20, Threshold 0.008
Brute Force GI
Time: 2m35s
best
Stefan
Most of the time I ended up with a lot of noise from GI or stuck buckets on refraction parts in my scene.
The following are the settings I ended up with and got super fast renderings.
Physically Based vs Artistic Flames
First thing I noticed was, that my overly bright flames came from the Physically Based Setting in the Fire Tab of my Volume Grid.
When I turn this setting down to 0 and go for an artistic approach, I can crank up the Fire multiplier to get the brightness I want out of my flames, and also the illumination I want.
This gives me the brightness I was expecting out of my flames. (I used a explosion simulation from the new Bifrost Graph)
Volume Light Cache vs Probabilistic volumetrics
So I read over in the VRay for Houdini Forums that I should completely deactivate the Volume Light Cache and use the Probabilistic Volumetrics Option in VRay Render settings Overrides under Volumetics Tab instead.
Immidiately my render speed increased and RAM usage went down 30%. Using this setup got rid of my stuck buckets and rendered nicely all over my scene.
Furthermore the Volume Light Cache setting produced too much noise on many of my explosions.
Fire Lights, Ray-Traced Smoke Color
I can even turn off Create Fire Lights and switch Smoke Color to Ray-Traced (GI Only). I am getting constant, fast, predictable renderings without any stuck buckets or too much noise.
Light Cache GI vs Brute Force GI
There is even pretty much no speed difference when switching from Light Cache over to Brute Force, wich was not possible before.
Those settings are fast to setup without having to trial an error and render super fast. At least for me and for now, so there is no guarantee that those settings arte best for everything and for everyone.
Imho the VRay documentation and the Volume Grid Shader settings have to be updated soon.
They discussed this topic in here also:
https://forums.chaosgroup.com/forum/...cache-concerns
https://forums.chaosgroup.com/forum/...tion-fireflies
Testrendering 58 Frames 600x600px, Min Subdivs 1, Max 12, Threshold 0.02
6min on Threadripper 3970x
https://we.tl/t-VGwNoEAfsJ
1200x1200px, Min subdivs 1, Max 20, Threshold 0.008
Brute Force GI
Time: 2m35s
best
Stefan
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