1. A computer-implemented method for generating a circular scratch highlight, the method comprising: accessing a plurality of texture planes, wherein each texture plane includes a plurality of copies of a texture oriented in the same direction; accessing a combined texture by combining the plurality of texture planes at different angles; applying the combined texture to a surface of an object; calculating a specular gradient vector based on a light vector, a normal vector, and a view vector, wherein the specular gradient vector points in a gradient direction of a specular highlight; and generating the circular scratch highlight by assigning, for each of a plurality of points on the surface of the object, a separate weight value corresponding to each texture plane in the combined texture based on how closely an orientation of the texture plane at the point corresponds to a scratch vector that is perpendicular to the specular gradient vector.