Separable Subsurface Scattering

less than 1 minute read

I’ve recently implemented Screen-Space Separable Subsurface Scattering into my rendering engine.  This implementation is based off the incredible work that’s been done over the past several years, and documented here and here.  I’m quite pleased with the results I’m getting from the effect and so am posting a few screenshots of it in action.

The first screenshots show the effect in daylight.  Hopefully it’s quite obvious which head in the picture has the new technique applied and which is being lit with the engine’s standard lighting model.

Effect Off Effect On

The second screenshot shows another part of the overall effect, which is the transmittance of light through very thin slabs of materials, such as ears.

Transmittance 1

The next screenshot better shows both subsurface scattering and transmittance working together.  In particular, notice how the light behaves along the ridge of the nose.

Transmittance 2

Finally, I cobbled together a quick setup showing how this technique could be used to create a nice effect for candles.  To make the effect, I added a wax-like kernel, and just aimed a bright spotlight straight down at a cylinder.

Wax Kernel