# Chapter 16. Real-Time Approximations to Subsurface Scattering — Simon Green

- Source: https://developer.nvidia.com/gpugems/gpugems/part-iii-materials/chapter-16-real-time-approximations-subsurface-scattering
- Note: add-only excerpt; images/code truncated.

## Summary (full chapter read)
Foundational real-time SSS toolkit; Gems3 Ch14 skin builds on texture-space diffusion lineage.

### Visual cues
Softens lighting; bleeding; detail loss; skin reddish terminator (blood); strongest where thin (ears/nostrils).

### Wrap lighting
`(N·L + wrap)/(1+wrap)`; LUT can bake red tint near terminator + specular power in alpha. Cheap skin look / Oren-Nayar-ish matte.

### Depth-map absorption (Hery-style)
Light-view depth like shadow map; `s = d_exit − d_entry` estimates path length through object; drive Beer–Lambert / color. Convex-only (holes wrong); “gummi lights” risk showing backface detail.

### Texture-space diffusion (Borshukov–Lewis)
VS remaps UV→NDC to unwrap mesh; light into 2D map; separable Gaussian blur (wider for R on skin); reapply as diffuse. Decouples shading cost from screen res; needs non-overlapping UVs, fairly uniform param.