hair.shader

A hair or fur strand.

Its specular is a pair of offset bands rather than one spot: a fibre reflects into a cone around its own axis, so the highlights are taken around the world tangent — which on strand geometry runs root to tip. fibre_color tints the second, broader band and is what switches both on; fibre_shift sets how far apart they sit and fibre_roughness how narrow the first one is.

Colour comes from base_color times the per-vertex colour, so a groom carries its own root-to-tip gradient under one material. transmission_color and transmission are the light that carries through a strand — the glow along a backlit edge.

Both faces of a ribbon stand for the same round fibre, so back faces are lit like front ones.