European Union, Commission of the European Communities
ESPRIT Open Long Term Research Programme
SIMULGEN
Realistic Simulation of Light for General Environments
ESPRIT Project #35772
Deliverable 1.3: Technical Report
Efficient Glossy Illumination with Interactive Viewing
Marc Stamminger, Annette Scheel, Xavier Granier, Frederic Pérez-Cazorla, George Drettakis, François Sillion
October 7, 1998
Abstract
One of the two goals of Phase I of SIMULGEN is the development of finite-element solutions for glossy global illumination, containing directional information suitable for interactive display. Previous state of the art has provided initial tools to achieve this goal, and the research and development performed during the first phase of SIMULGEN has significantly advanced this domain.
The need for the representation and visualisation of glossy surfaces in the context of a global illumination solution and system is evident. Real-world scenes are not completetly diffuse, and in many cases glossy surfaces play an important role in the overall illumination of a scene. Glossy illumination participates in direct and indirect lighting, and thus it must be treated in the global illumination context.
Previous solutions for glossy scenes have almost all been "static image-oriented" precluding any possible interaction with the scene. As a result, walktrough based systems have been limited to diffuse-only surfaces, and thus have a "plastic", "artificial" look to them. In this work, we have advanced previous research, allowing the development of much more solid and complete solutions, which allow the interactive display of simple, but interesting, glossy scenes.
The technical report can be separated into three main parts:
The representation of directional distributions. The data structure used to represent directional functions, in particular outgoing radiant intensity is central to any glossy solution. We have studied the problems in-depth and evaluated several alternatives.
The Illumination Samples Algorithm. We have developed a new algorithm which uses a new way of representing incoming radiance, and a new reflection algorithm which, as the results will show, is beneficial both in memory and in computation time.
Interactive Viewing Algorithm. Once a suitable finite-element representation has been created, we need to rapidly view the result. We have presented a new heuristic approach which achieves significant improvement in speed compared to previous approaches.
