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Sub Surface Scattering

Posted: Fri Nov 13, 2020 5:47 am
by SparkieShock
Hey .. trying, once again, to get SSS to work on DAZ Skins.

I tried this a few weeks ago and was actually able to see changes on the skin of a character but after trying on others I'm back to seeing no change .. no matter what I alter on the Scattering node.

So, I'm thinking that whatever model I was working on where this worked must have been using a 'specular' node. It seems scattering works best on that. But my question is .. why doesn't it work on Diffuse? It doesn't seem to work at all. Why does Diffuse have the plugin module for the Scattering node if it simply does nothing?

All I'm trying to do is to get the skin to have some translucency. Not like be seethrough or anything .. but I just want the nose and ears and lips to have that nice SSS effect. I can do this so easily in blender but not in Octane. Can someone please clear up this mystery for me once and for all.

Does Scattering on Diffuse do anything? .. And if it does .. how do you get it to work.
If it doesn't? .. why is it there at all?

And above all else .. how do I get some translucency on my skins?

Re: Sub Surface Scattering

Posted: Mon Nov 16, 2020 4:30 am
by valzheimer
For skin it's best to use the Mixed Material with Specular and Diffuse material mixed in. Diffuse does have scatter but it's not what you'd expect from translucent skin, that's why you add Specular in the mix to get some refraction between surface and subsurface layer as more realistic formula. Look up Tonysculptor examples in DB to see how these nodes work together to create translucent skin.

You may also try the new Universal material with randomwalk SSS, I've seen people getting some good results even though I haven't found really practical use for skin shading in it yet.

Hope that help.
V.

Re: Sub Surface Scattering

Posted: Tue Nov 17, 2020 6:14 pm
by Sorel
Specular/volume materials really do seem the best to get a good skin. I have tried using the diffuse method before but never really liked the results. This was my most recent I did with the random walk sss. it was a diffuse/diffuse each with a specular layered material for the shine. And while initially I thought it looked good, I found it still didn't seem right. I'm currently working on something using just a specular node with random walk sss and am having results which seem better.

Re: Sub Surface Scattering

Posted: Wed Nov 18, 2020 1:33 am
by Banti
Sorel wrote:Specular/volume materials really do seem the best to get a good skin. I have tried using the diffuse method before but never really liked the results. This was my most recent I did with the random walk sss. it was a diffuse/diffuse each with a specular layered material for the shine. And while initially I thought it looked good, I found it still didn't seem right. I'm currently working on something using just a specular node with random walk sss and am having results which seem better.
Random Walk on specular material is definitly the way to go for the best looking skin. It does have its drawbacks tho.
First, specular material, especially scattered ones, take a lot of time to render. You also need decently high diffuse and specular depths to work which also increases render times.
Second, I often render interior scenes that are not always brightly illuminated. This material will look terrible in low light settings as it needs a good amount of light to look good. If there is not enough light the specular material will look terribly noisy and just awfull in general.
You can get okay results with using random walk on diffuse material in those scenes but everytime I compare it to glossy skin shaders, I dont see much of a difference. So for indoor scened i tend to use glossy or diffuse with specular layer.

Re: Sub Surface Scattering

Posted: Thu Nov 19, 2020 8:46 pm
by Sorel
It seems I lied. The image i attached is was made using the specular style with random walk. I forget how far I progress on my projects sometimes lol. But more specifically it is the universal material with full specular, no diffuse

Re: Sub Surface Scattering

Posted: Sun Jan 24, 2021 3:38 pm
by rajib
SparkieShock wrote:Hey .. trying, once again, to get SSS to work on DAZ Skins.

Does Scattering on Diffuse do anything? .. And if it does .. how do you get it to work.
If it doesn't? .. why is it there at all?

And above all else .. how do I get some translucency on my skins?
It definitely is best to mix a Diffuse with the Specular node to get SSS or use the Random Walk node. But in any case do remember to add 'Transmission' in the Diffuse node. The light needs to pass through the Diffuse materials for the scattering of the light to occur. Specially if you are not mixing a specular material with the Diffuse. Generally the mixed Specular material provides the Transmission Pin value to allow the light to pass through.