AVAILABLE FOR : HOUDINI
Here we’re using SSSRandomWalk with a map controlling the amount of translucency. Translucency here is not the general amount of subsurface scattering (which is controlled as usual with color, radius and scale) but the amount of non-exponentiality in the random walk. Arnold Standard Surface does only exponential random walks; our shader instead does also non-exponential walks. Non-exponential vs exponential refers to the decay of light when travelling in the medium. From physical measurements it turns out that most SSS materials exhibits both behaviours.
Marble is one of those materials where non-exponential light decay gives nice nuances to the model. Remember that our nodes come with all the lobes necessary to rig a full model.. ie. if you don’t have special needs for other specular layers you can directly use those that come with the SSS node for a super easy and fast PBR workflow. Ie. it simply works as the Arnold Standard Surface but for the same amount of samples, it is faster with better convergence and with extra parameters.
Refer to this page for documentation : SSS Random Walk