The degree to which a material appears smooth, affecting both diffuse and specular response.
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- Model I/O
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
map attributes when importing from the MTL file format (for assets in the OBJ file format).