VrayScatterVolume faster/better than EnvironmentFog (?)

[LudvikKoutny]

Hi,

so I've been working on a scene recently, and it started to get really slow for some unknown reasons, so when I got into optimizing it, one of the things I tried was replacing VrayEnvironmentFog with Box that has VrayScatterVolume, as I suspected that EnvironmentFog may be one of the major culprits of the poor performance.

What I found out is not only does VrayScatterVolume seem to be significantly faster, it also seems to look somewhat better, and as a bonus, it has a phase function, a thing I've requested long time ago for EnvironmentFog, but got somehow forgotten. IT really helps making godrays pop.

So if anyone is using EnvironmentFog in your scenes for global volume, give VrayScatterVolume a try. Just make sure to set bounces bounces to 1, if you want to bring it on par with EnvironmentFog that has scatter GI option disabled

[vlado]

Yeah, I've been meaning to unify the code between the two, the scatter volume is newer and better in some respects.

Best regards,
Vlado

[LudvikKoutny]

Yeah, I've been meaning to unify the code between the two, the scatter volume is newer and better in some respects.

Best regards,
Vlado

I'd be very happy about that

[olika]

Thanks for that tip, sound very interesting,
never touched the scatter volume material though,
could you explain this a little more?
Put a Box around my outdoor scene,vrayscattervolume material on it, but nothing happens?
Do i have to exclude include something? Or use a boxgizmo something? Thanks in advance

[Svetlozar Draganov]

Does the fog renders fine if camera is outside of the box?
If yes, then you can wrap a camera into a small spherical object mapped with the same material as the box, and the fog should render fine when camera is inside the box.

[olika]

Hi Svetlozar,
thanks for reply,
tested a bit more, seems it renders fine if camera is outside watching at the box and the teapot,
but with the big environment box and a sphere around the camera nothing happens... ;-(

[Ihno]

Invert the faces of the sphere. You need front faces in front of the camera to give vray a idea where it starts, back faces end the scattering. Same as the fog in a vraymtl.
Thanks for digging this up I must have overlooked it.
I played a little bit with this approach and I like it too.
1+ for scatter volume environment fog.

[Undersky]

Thanks for this! I've always thought the workflow with Env Fog is rather crappy. How you deal with volumetric fog in Redshift, with a contribution multiplier and a phase function, is really fast and easy, and with this, although it takes a bit more to setup, it works essentially the same (expect the speed though =)

[Mnietek2707]

... you can wrap a camera into a small spherical object mapped with the same material as the box, and the fog should render fine when camera is inside the box.

I can't get this to work.
Could you please provide example scene?