SSS and clouds

WAS · December 26, 2020, 07:16:05 PM

When I use clouds for like fog, and stick a SSS model in it, it seems to glow with the cloud colour, despite volume density and colour at one and even ramping down decay distance to nearly nothing. So when I mix together the SSS and default shader, the transmission areas are glowing. This explains why I couldn't use SSS on my Derelict scene because of the godrays haze. I thought it was just scale and I couldn't find a sweet spot for SSS and gave but, but even here, reducing to nothing doesn't help.

First screen: SSS only
Second screen: SSS Only
Third screen: Default shader only

Hannes · December 27, 2020, 06:13:12 AM

Confirmed.

Hannes · December 27, 2020, 06:55:44 AM

So, unless Matt has a solution for this, I'd say rendering an extra atmosphere (fog-) pass and comp everything together later would be a compromise.

WAS · December 28, 2020, 03:01:42 PM

Quote from: Hannes on December 27, 2020, 06:55:44 AMSo, unless Matt has a solution for this, I'd say rendering an extra atmosphere (fog-) pass and comp everything together later would be a compromise.

I don't think that would be satisfactory for the planned scene with water surface reflections, lighting from the fog on objects/plants/scene etc. All the elements would just be rendered in pure sun with a opacity haze overlayed in comp in my head; where there would be no proper calculation in lighting and colour.

Hannes · December 28, 2020, 04:24:17 PM

Yes, it would only be a very cheap solution. So I hope Matt will chime in.

Matt · December 30, 2020, 01:32:04 AM

Can one of you provide a TGD? I have tried various ways to reproduce this but I haven't succeeded yet.

Hannes · December 30, 2020, 05:06:45 AM

Sure. No problem.

Matt · December 30, 2020, 06:37:44 AM

Thanks. I am working with it now to figure out what's causing it.

Hannes · December 30, 2020, 06:56:06 AM

Great! Thanks, Matt. Although this isn't my thread, I'm very curious about it, because I love to play with subsurface scattering and I never noticed this behaviour.
I also tried to increase the volume density and played with the decay distance like Jordan did, but it didn't solve the problem.

WAS · December 30, 2020, 04:25:29 PM

Yeah, definitely a little strange. It reminds me of when I was using a merge shader with a luminosity surface and a SSS surface to manually create this sort of effect.

The effect did actually look realistic on the eye. Now that I've looked at enough and compared IRL; how their eyes look underwater, so I may isolate the eyeball and actually do a merge with a luminosity shader for that effect.