[ Hair rendered using translucent shader. Render on the right demonstrates simulated back-scattering ]
Translucensy is added to this shader by tracking light travelling in both- parallel and perpendicular directions. Otherwise this shader is very much like the cheap shader. By setting a high transmittance value backscattering can be simulated (see example above). By setting very low reflectance and high transmittance you can simulate hair being very light-absorbant.
Parameters:
Reflection/Transmission - Control the balance between how much of the incoming (incident) light passes through, and how much of it gets reflected by the hair surface. Both these coefficients added together account for total hair volumetric scattering.
