Mapping uv-coordinates

Uv-coordinates are used to define how a texture is mapped on to some geometry. However, uv-coordinates are also used when you have a surface with anisotropic reflections. The layout of the uv-coordinates defines the direction of the reflections on the surface. Just imagine it as the brush direction in case of brushed metal. Ensure that the uv-coordinates are well placed for anisotropic reflections. The orientation of the mapping effects the orientation of the anisotropic reflection.

Figure 1. Anisotropic material on an object with planar uv-mapping.

Figure 2. Anisotropic material on an object with spherical uv-mapping.