A vector model for global illumination in ray tracing

This paper presents a method taking global illumination in ray tracing into account. A vector approach is introduced which allows to use any type of material, in particular with directional properties. This vector is decomposed into a direct component associated to light sources and an indirect one which corresponds to light having been reflected at least once. These components are estimated at a small number of points within the scene. A weighted interpolation between known values allows to reconstruct these components for the other points, with the help of a gradient computation for the indirect component. Computed images are thus more accurate, at almost no additional cost, and no discretizing of the geometry of the scene is needed.