How Do Games Render Fur?

Rendering fur and hair in real-time games is extremely challenging due to geometric complexity (100k+ strands), complex light interactions (subsurface scattering, transparency), and physics simulation. Shell texturing is a decades-old technique that fakes volumetric fur/grass/moss by stacking multiple simple mesh layers (shells) with noise-based transparency masks. The video explains how to implement it: generating random strand presence via UV-based hashing, extruding shells along vertex normals, tapering strand thickness with height, applying Half-Lambert diffuse shading, and adding basic gravity-driven hair displacement. Key drawbacks include visible layer gaps at grazing camera angles and severe overdraw with high shell counts. Real-world examples include Viva Piñata, Dark Souls (Sif), and Genshin Impact. Mitigations include camera restrictions, minimal shell distances, and stylized non-realistic lighting.