LuxCoreRender Forums

Hi guys,

Tried the SSS example scenes, many thanks, BYOB and Sharlybg!

The scenes gave me some valuable new insights into Luxcore SSS.

Sharlybg, I'm curious why you used an Invert node in your SSS setup:
Image 1.png

Does the Scattering color absorb that color inside the volume, in stead of ...

Thanks a lot, B.Y.O.B., much appreciated!

I will have a thorough look at your scene tomorrow morning.

Yeah, the SSS Radius is an RGB value. I often plug the color in that slot as well, to emphasize the SSS color, as the RGB node has a three-fold vector output corresponding to the SSS Radius RGB ...

Sharlybg wrote: Tue Nov 03, 2020 6:13 pm Can you just make a simpe scene of your Cycles SSS applied to luxball so that we can just convert it to Lux for you ?

There's no special node setup. Here's how the SSS material looks in Cycles: Thanks in advance if you want to give it a try.

:) Yeah, but I love the gradually diminishing, glowy light as surface depth progresses in Cycles. I tried all advice I've read and viewed, and just don't succeed in achieving that effect in Luxcore. Either the whole surface gets lighter or light doesn't penetrate a surface enough.

But I've sent my ...

Thanks, I know the video. Good tips, but despite that knowledge I can't get Luxcore SSS to behave as Cycles Random Walk SSS.

I've tried just about everything, but I'm happy to send the scene to you in a PM.

OK, tried to match the advice in the Luxcore Wiki SSS page some more, but when I leave both the Glossy Translucent material's Transmission color and the Volume's Scattering value white, colors become very faint, and the bump map starts looking like artifacts:
Happy Halloween by Metin Seven ...

Have you read this? https://wiki.luxcorerender.org/Subsurface_Scattering
It explains some of the fundamental principles of using SSS in LuxCore.


I used Random Walk SSS in Cycles, which is the same algorithm as LuxCore uses, unless I'm mistaking.

This is correct.


Slightly closer again ...

OK, adjusted the light strength of both the HDRI environment as well as the direct lights to get more light energy going and match the Cycles scene more.

It looks a bit brighter now, but still not the nice light falloff inside the volumes.

I'm using the same HDRI with the same orientation. Luxcore's diffuse shader gives a very different result on the background, hence the visible difference. But if you focus on the pumpkin you see similar brightness.

Nonetheless, I'll change some light settings to see if that really changes the SSS ...