Integration Methods for Galerkin Radiosity Couplings

Reid Gershbein

Sixth Eurographics Workshop on Rendering '95


Computing energy transfer between objects is the most expensive operation in radiosity systems. This energy transfer operation, known as the irradiance operator, is an integral that, in general, must be calculated numerically. We wish to increase the speed of this computation without severely compromising fidelity and perform a study of numerical integration techniques, known as quadrature methods. A theoretical discussion of numerical integration is presented followed by specific details of the studied methods. The results of our study show the strengths of gauss quadrature rules and insight into greatly reducing the cost of the irradiance operator while maintaining accuracy. An adaptive method for choosing Gauss quadrature rules is presented, and our performance analysis of the new adaptive algorithm shows that it can be up to 10 times faster than previous methods.

Additional information

PostScript version of full paper without color plates.

Plate 1

Last update: 13 April 1995