Invited Paper.- Trends in Radiosity for Image Synthesis.- 1. Efficient Ray Tracing Methods.- Incremental Ray Tracing.- Parametric Surfaces and Ray Tracing.- 2. Theory of Global Illumination Models.- A Theoretical Analysis of Global Illumination Models.- Physically Based Lighting Calculations for Computer Graphics: A Modern Perspective.- Efficient Radiosity Methods for Non-Separable Reflectance Models.- 3. Photometric Algorithms.- A Progressive Ray-Tracing-based Radiosity with General Reflectance Functions.- A Two-Pass Radiosity Method for Bézier Patches.- 4. Form Factor Calculation.- The Hemisphere Radiosity Method: A Tale of Two Algorithms.- Exploiting Coherence for Clipping and View Transformations in Radiosity Algorithms.- A Rapid Hierarchical Radiosity Algorithm for Unoccluded Environments.- Fast Radiosity by Parallelization.- 5. Physics Based Methods.- Newton's Colors: Simulating Interference Phenomena in Realistic Image Synthesis.- Light Sources in a Ray Tracing Environment.- Methods for Efficient Sampling of Arbitrarily Distributed Volume Densities.