Chapter 14. Advanced Techniques for Realistic Real-Time Skin Rendering — d'Eon, Luebke
- Source: https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-14-advanced-techniques-realistic-real-time-skin
- Volume: GPU Gems 3
- Note: add-only excerpt for wiki ingest; images omitted; prose and key listings kept.
Summary of full chapter read
Physically based real-time skin: specular (Kelemen/Szirmay-Kalos ≈ Torrance-Sparrow) + multilayer diffusion SSS.
Specular
~6% white dielectric Fresnel (F0≈0.028, η≈1.4). Schlick from H. Beckmann NDF via 2D lookup (m, N·H). Weyrich facial region maps for m and ρ_s. Always white specular in linear space.
Diffusion profiles
Multilayer skin needs multipole shapes (Donner & Jensen); dipole alone looks waxy. Fit R(r) as sum of Gaussians (6 for three-layer Caucasian model). Gaussians separable → hierarchical separable blurs.
Texture-space diffusion (improved Borshukov/Green)
Irradiance unwrap → stretch-correction map (ddx/ddy world) → successive 7-tap separable Gaussian blurs keeping each level → final linear combine with RGB Gaussian weights. Pre-/post-scatter color mix. Optional energy conservation via preintegrated ρ_dt(N·L, m).
Modified translucent shadow maps
For ears/nostrils: TSM stores distance + light-facing UV; thickness + Gaussian 3D separability reuses blur textures for transmission. Distance correction and blurred thickness reduce artifacts.
Also
Sum-of-Gaussians accelerates HDR bloom (2 Gaussians ≈ (1−r/d)⁴). Seams need special handling.