Falloff Map

The Falloff map can be used to control the blend of two materials depending on the viewing angle of the material's geometry. This can help simulate coating effects commonly visible in car shaders or layered effects commonly visible in velvet cloth or frosted glass.

This can also be used to mimic architectural glass for glossy and specular materials by plugging the texture into the opacity channel of the material node allowing light to pass through based on the falloff texture.