The Sheen Layer can simulate the grazing coloration or rim lighting in fabrics like velvet. It can also simulate layers of dust.
Sheen - The Sheen layer's color.
Roughness - The Sheen layer's roughness. Higher values spread the sheen color to larger parts of the surface.
Affect Roughness - The percentage of roughness affecting the subsequent layer's roughness.
Bump - Creates fine surface detail by simulating a relief using a Greyscale texture interpreted as a height map.
Normal - Creates fine surface detail by distorting normals using an RGB image.
Layer Opacity - Controls the Layer opacity with a Greyscale texture.