The goal of this book is to present the most advanced research work in realistic computer generated images. It contains the papers presented during a Eurographics workshop held in Rennes, France, in June 1990. The objective of this workshop was to assemble experts from physics and computer graphics to contribute to the introduction of physics-based approaches in the field of computer generated images. The book begins with an overview on realistic imagery that discusses the main issues in radiosity and describes the most recent developments. The first chapter gives a description of improved ray tracing techniques for animated scenes and parametric surfaces. The second chapter develops the theoretical aspects of global illumination models. The third chapter presents two algorithms that try to combine radiosity and ray tracing to cope with a wide class of photometric problems. The fourth chapter describes techniques aiming at efficient evaluation of form factors. The last chapter gives examples showing how physics can be used to solve some rendering problems such as interference, simulation of area light sources, and light propagation through media.