Generating accurate radiosity solutions of real world environments is user-intensive and requires significant knowledge of the method. As a result, few end-users such as architects and designers use it. The output of most commercial modeling packages must be substantially "cleaned up" to satisfy the geometrical and topological criteria imposed by radiosity solution algorithms. Furthermore, the mesh used as the basis of the radiosity computation must meet several additional requirements for the solution to be accurate.A set of geometrical and topological requirements is formalized that when satisfied yields an accurate radiosity solution. A series of algorithms is introduced that automatically processes raw model databases to meet these requirements. Thus, the end-user can concentrate on the design rather than on the details of the radiosity solution process. These algorithms are generally independent of the radiosity solution technique used, and thus apply to all mesh based radiosity methods.

This paper describes a novel implementation of the progressive refinement radiosity algorithm. Algorithm performance is greatly enhanced using the capabilities of a multiprocessor graphics workstation. Hemi-cube item buffers are produced using the graphics hardware while the remaining computations are performed in parallel on the multiple host processors. Speedups of a factor of 40 or more over the equivalent software implementation are observed. Load balancing issues are discussed and a system performance model is developed based on actual results.Additionally, a new user interface scheme is presented where the radiosity calculations and walk-through tasks are separated. At each new iteration, the radiosity algorithm automatically updates colors used by the viewing program via shared memory while simultaneously obtaining hints on where to further refine the solution.

Current radiosity methods rely on the calculation of geometric factors, known as form-factors, which describe energy exchange between pairs of surfaces in the environment. The most computationally efficient method for form-factor generation is a numerical technique known as the hemi-cube algorithm. Use of the hemi-cube is based on assumptions about the geometry of the surfaces involved. First, this paper examines the types of errors and visual artifacts that result when these assumptions are violated. Second, the paper shows that these errors occur more frequently in progressive refinement radiosity than in the originally proposed full matrix radiosity solution. Next, a new analytical technique for determining form-factors that is immune to the errors of the hemi-cube algorithm is introduced. Finally, a hybrid progressive refinement method that invokes the new technique to correctly compute form-factors when hemi-cube assumptions are violated is presented.