The Sheen rollout is part of the V-Ray Material parameters.
Sheen
The Sheen layer can be used to create cloth materials such as satin.
Sheen Color – Specifies the color.
Texture – A texture map can be specified here for the sheen color.
Mix Strength – Specifies a blend amount between the texture map and the color.
Sheen Amount – Specifies how much the sheen layer overlays the diffuse color. The higher the amount, the more of the sheen color you get. A Texture can be attached to this slot and blended with this value, using the Mix Strength option.
Sheen Glossiness – Controls the sharpness of reflections. A value of 1.0 means all of the light reaches the diffuse color, and when the value is smaller, the cloth material looks glossier. See the Sheen Glossiness example for more information.
Example: Sheen Glossiness
This example shows how changing the glossiness parameter of the sheen layer affects the material. The Amount is set to its default value of 1.