Problem with unusable noisy Environment Fog

V-Ray V-Ray for Maya Issues
1

Hello,

I’m new with rendering fog and have built a test scene.

It took me a day of testing and it’s always slowly and noisy…
I tried now every setting. (Subdivs, step size, Scatter GI, Rendersettings…)

Attached some screenshots.
I created a cube and attached VrayEnvironment fog with VrayMaterial (opacity 0 and Fog as volume material to SG)

Lights:
There are only 2 rectangular lights attached to the set (“override light shapes”), but it takes like 10 minutes to get a grainy result and it never gets fine.
There are originally 9 Lights, I switched all others off to be sure they don’t affect anything.

A texture still is not applied (because if the “base fog” doesn’t work, it only would make it more complicated).

A final render in 1200 pixels would take 30 minutes and I stopped it, because it looks grainy, too.
When I see tutorials or show reels it goes instantly. In my setup it needs liek 5 moinutes until even it starts to show a picture…

Thanks for help!

VrayNext, Maya2018.6, CPU (on good doubleCPU workstation. also tried GPU render with 2 gtx1080ti but it is is not faster)

that's a started CPU standard rendering, stopped after 10 minutes....jpg
that's a started CPU standard rendering, stopped after 10 minutes....jpg423×573 75.7 KB

tried GI depth 3 and GI depth 4, too.jpg
tried GI depth 3 and GI depth 4, too.jpg545×305 18 KB

setup with 2 rectangular lights (directional).jpg
setup with 2 rectangular lights (directional).jpg862×745 85.3 KB

.jpg.jpg
.jpg.jpg391×612 27.3 KB

2

Chaos Docs there are some general tips on rendering volumes, try probabilistic rendering for example.

Have you set the shape type of your lights to disc by any chance? I’ve had trouble with those being much much slower than regular rectangle lights

3

Thanks. The main issue really only was the step size. When it is too small, it’s not rendering correctly. In the manual is recommended to have a half or third of the fog distance.