Parallel Radiosity without Form Factors

We reformulate the radiosity equation in terms of the radiance of light rays rather than in terms of pairs of surface facets, and develop an algorithm for solving it using a coordinate evolution on the set of light rays in a scene. There are two key advantages to the new formulation. First, coordinate evolution is naturally embedded in a massively parallel SIMD architecture. The result is an alternative, parallel solution to the visibility problem, which is the main bottleneck of traditional radiosity approaches. Second, the new formulation is general. The algorithm may be extended to include non-isotropic surface reeectance and participating media such as fog or smoke. Examples are presented for the standard case of Lambertian surfaces in a vacuum, as well as for the case of isotropic scattering and absorption in free space.