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The Subsurface Scattering in Principled BSDF is a bit confusing:

  • Where can I find some recommended presets (like in other software)?
  • What is the main difference between SSS Color and Radius?
  • (Technical papers don't help very much, I'm not an engineer)

enter image description here

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Subsurface slider

  • Use it to scale Scattering depth down to realistic values
  • When set to 0, scattering is disabled

Values of around 0.01 are normal, since you're usually scaling from meters to milimeters.


Subsurface Color

  • Primary color. Visible on opaque parts and in shadows.
  • Generally, use the same image/color you used for Base color to avoid color mixing

Subsurface Radius aka Scatter Color

  • Secondary color. Visible on edges and translucent parts (like ears).
  • Connect an RGB node or a texture. This is a good place for a subdermal map.
  • The RGB values here represent how deep light penetrates in meters (!).

Correct radius is important to get right. Scale it down using the Subsurface slider.


Example of SSS setup

Stanford Dragon, 15 centimeters
Marble values set from reference chart below
Subsurface slider set to 0.01, to match SSS depth of marble (~8.5 milimeters)

enter image description here


Recommended values chart

Size matters: For SSS to work correctly, your model needs to be in real world scale.

enter image description here

Source chart from Pixar. Original paper here.


Sources
Link - Henrik Wann Jensen, Stephen R. Marschner, Marc Levoy and Pat Hanrahan: "A Practical Model for Subsurface Light Transport". SIGGRAPH'2001.
An Introduction To Real-Time Subsurface Scattering, Stanford Dragon - Stanford University Computer Graphics Laboratory, Subsurface - Arnold Renderer, Subsurface - Substance Painter, Subsurface - Renderman

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