Radiosity Introduction

The radiosity approach to rendering has its basis in the theory of heat transfer. This theory was applied to computer graphics in 1984 by Goral et al.

Surfaces in the environment are assumed to be perfect (or Lambertian) diffusers, reflectors, or emitters. Such surfaces are assumed to reflect incident light in all directions with equal intensity.

A formulation for the system of equations is facilitated by dividing the environment into a set of small areas, or patches. The radiosity over a patch is constant.

The radiosity, B, of a patch is the total rate of energy leaving a surface and is equal to the sum of the emitted and reflected energies:
Radiosity was used for Quake II