The Standard Surface shader is a physically-based shader capable of producing many types of materials. It includes a diffuse layer, a specular layer with complex Fresnel for metals, specular transmission for glass, subsurface scattering for skin, thin scattering for water and ice, a secondary specular coat, and light emission.
This shader models a material consisting of ten components that are layered and mixed hierarchically as illustrated in the diagram below. The properties of individual components can vary across the surface.
By default, the parameters are appropriate for materials such as plastic, wood or stone. By setting a few key parameters to 1, different types of materials can be quickly created:
Parameter values between 0 and 1 may be used to create more complex materials that are a mix of basic material types.
Standard Surface is energy conserving by default. All its layers are balanced so that the amount of light leaving the surface does not exceed the amount of incoming light. For example, as a surface is made more metallic and the specular layer contribution is increased, the diffuse layer contribution is reduced accordingly to ensure energy conservation.