Enumeration Case

MDLMaterialSemantic.roughness

The degree to which a material appears smooth, affecting both diffuse and specular response.

Declaration

case roughness = 6

Discussion

At lower values, the material appears shiny, with well-defined specular highlights. At higher values, a diffuse material becomes retroreflective, and specular highlights are very spread out.

Model I/O uses this semantic for the roughness and map_roughness attributes when importing from the MTL file format (for assets in the OBJ file format).