Yarn-based Cloth Shader : (aka) micro-fiber based BRDF : micro-fibers orientation returns correct physically-based macro specular highlights, suitable for both close-ups and distant views.
Automagic color shifting, normal/bumps simulated with specular roughness for improved detail and consistency. Here we see also fiber fuzziness in action.
Procedural weaving pattern support via WIFs (Weaving Information Files) files.
Hanrahan-Krueger to simulate additional diffuse scattering (the fabric model itself uses an ad-hoc phase function to describe the scattering inside the yarn and to simulate the way light interacts with fibers).