Participating media illumination using light propagation maps

Light traveling through semi-transparent media such as smoke and marble is absorbed and scattered. To achieve proper realistic visualizations of such media, illumination algorithms must account for these events. In this article, we present a new method for solving the Radiative Transport Equation, which models such evolution of light. The new method falls into the category of the Discrete Ordinates Method and inherits its generality and computational lightness. This method is known to suffer from two main shortcomings, namely false scattering and the ray effect, which we avoid in our new method. By propagating the light using low-dimensional maps of rays we detach their transport from the Eulerian grid and use fine angular discretizations. Thus, the scattering effect at each scattering generation is eliminated and the ray effect is significantly reduced at no additional memory requirements. Results demonstrate the new method's efficiency, ability to produce high-quality approximations, and its usefulness for a wide range of computer graphics applications.