Metal is the same as plastic except that the specular component is coloured by the material. Define the R, G, B reflectance values and the specularity and roughness. Specularity and roughness have the same theoretical limits as given above. However, metal materials are reflective and the usual range for specularity is 0.5 – 1.0, and for roughness a range of 0.0 – 0.5.
