The degree to which specular highlights elongate in the direction of the local tangent basis.
- iOS 9.0+
- macOS 10.11+
- tvOS 9.0+
- Model I/O
This semantic has no effect in a mesh that does not contain vertex attribute data providing a tangent basis.
Model I/O uses this semantic for the
map attributes when importing from the MTL file format (for assets in the OBJ file format).