1. A method for automatically generating factored approximations for an arbitrary reflectance distribution function, comprising the steps of: (1) selecting an initial set of projections and textures; (2) establishing a search space; (3) searching the space for a set of optimal factors of the function; (4) building a full approximation of the function from the set of optimal factors of the function; and, (5) computing reflectance values for arbitrary viewing angles using the full approximation of the function.