Random walk subsurface scatering artifacts

whenever i use random walk sss ther’s a blue tint around mouth and eyes idk how to solve this is it related to geometry or how colose the faces are or so cause the lips barely touch but not intersect and i dont find any solution except lowring the strength which kill the effect of light scatering and looks more like diffuse
for units i am using real life scales so 0.1 subshrface is kinda resonable i guess

Sss radius expects a vector, why are you connecting a rgb value to it?

no not that i saw this back then being used even in the blender studio instead of just pluging values u can plug the rgb node
same result
colors output 3 channles too so same thing
not the problem tho it’s in the random walk methode and i guess it’s about geometry that’s why i am asking
thanks tho

Try to disconnect the color from subsurface radius and instead manually give the 3 channels the same value (that value will control the SSS distance and is the only value that’s affected by the scale of your object). Then, make sure the texture going into the subsurface color is tinted red. This will make the SSS color entirely controlled by the texture, without any difference caused by depth.

If you give all the 3 channels the same value you are going to give the R, G and B channels of SSS all the same radius, resulting in a white SSS effect. In this case, I believe he should lower the luminosity of the RGB node dragging the grey tone slider to control the extend of the radius and avoid the values to be too high.

I am not sure if it helps with the blue tint though.

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Making the 3 channels the same would indeed make the SSS white, but then you can use the subsurface color to make it red again by using a red texture. Of course you then then lose the more physically correct effect, but you gain full control over the color. I do agree however that for this character, the radius should probably be lowered. That might even help the blue tint by itself.

If you use real life values, then “Multiply” RGB input node with “0.01”.

Subsurface color and subsurface radius have completely different effects on the SSS appearance. Subsurface color is the color of the subdermal scattered light and the radius is the light that passes through the flesh. You can see that the subsurface scattering color affects the whole surface of your model almost with the same intensity while the radius depends on the thickness of the mesh.

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I did some testing and I see what you mean, it seems I am not fully used to the way cycles treats SSS.

After a bit of trial and error, I find that I can cause the blue effect by giving a too large radius to the red channel. Also, I find that the default Suzanne model creates that effect easily around the eyes, but it disappears if I fill the eye sockets. After a bit of trial and error, It is totaly possible to get something that looks realistic.


that’s what i am talking about it have nothing to do with the rgb node it’s about the mesh
and i dont know how to fix it caus the normal sss is okay but using the random walk produce the blue tint
the mouth is closed from the inside it have teeth too i guess to close to the lips that they produce such thing
the eyes too are closed from the inside so i may see how to fix the mesh at least