Anisotropic map

An anisotropic map is a texture that controls the shape of the specular highlights from real-time lights, often used for hair shading. Anisotropic highlights are characterized by long directional strokes, instead of the typical circular shape.

The texture is usually called a Flow map which is very similar in concept to a normal map, except instead of controlling surface normals, it distorts the specular highlight in specific directions across the surface.

Anisotropic Tutorials

• Anisotropic Shader For Hair by Stephen Jameson provides a breakdown of a shader setup in the Unreal Development Kit (UDK).
• HAIR!? thread on Polycount by Paul 'Prolow' Lohman has some examples of an anisotropic hair shader in Maya.
• Making an anisotropic map for Marmoset Toolbag post on the Polycount forum from the Lead Engineer at 8monkey Labs.
• Deriving an anisotropic map from vectors post on the Polycount forum from a Character Artist at ArenaNet.
• Painting a "flow" normalmap? thread on the Tech-Artists.Org forum.
• HairTechnique on the wiki.

---