Volume 0 (1981), Number 0 pp. 1–27 COMPUTER GRAPHICS forum
The State of the Art in Interactive Global Illumination
, Tobias Ritschel1 2 Carsten Dachsbacher3 Thorsten Grosch4 Jan Kautz5
Télécom ParisTech / CNRS (LTCI)1 and Intel Visual Computing Institute2 Karlsruhe Institute of Technology3 University of Magdeburg4 University College London5
$
%
#
"
Figure 1: Photography of a scene with global illumination: Multiple diffuse and specular bounces, caustics and scattering.
Abstract The interaction of light and matter in the world surrounding us is of striking complexity and beauty. Since the very beginning of computer graphics, adequate modeling of these processes and efficient computation is an intensively studied research topic and still not a solved problem. The inherent complexity stems from the underlying physical processes as well as the global nature of the interactions that let light travel within a scene. This article reviews the state of the art in interactive global illumination computation, that is, methods that generate an image of a virtual scene in less than one second with an as exact as possible, or plausible, solution to the light transport. Additionally, the theoretical background and attempts to classify the broad field of methods are described. The strengths and weaknesses of different approaches, when applied to the different visual phenomena, arising from light interaction are compared and discussed. Finally, the article concludes by highlighting design patterns for interactive global illumination and a list of open problems.
Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Color, shading, shadowing, and texture / Radiosity / Raytracing
1. Introduction the underlying principles of light-matter interaction are well understood, the efficient computation is still a challenging Light in the real world interacts with surrounding media and problem. Many processes are so computationally expensive surfaces creating stunning visual phenomena such as color that they require the development of simplified models, tai- bleeding, reflections, crepuscular rays, and caustics. Need- lored algorithms and data structures. In this article we will less to say that the reproduction of the real world has been give a survey and classification focusing on interactive meth- the ultimate goal of computer graphics ever since. Although ods for computing light transport in virtual scenes (global