An energy-conserving sheen layer that can be used to approximate microfiber, cloth-like surfaces such as velvet and satin of varying roughness. Sheen is layered onto the diffuse component and its weight is determined with this attribute. Sheen can be thought of as the density or the combination of the density and length of the fibers.
The color of the fibers. Tints the color of the sheen contribution.
This modulates how much the microfibers diverge from the surface normal direction.