Why is Radiosity expensive, memory- and processor-wise?
Radiosity uses a lot of memory because all of the model’s geometry must be duplicated and converted into triangles of a certain size, and assigned energy values. The more detailed the geometry in a model, the more memory the Radiosity processing will use and the more time will be required to re-emit light energy from each triangle to its neighbours. Also, the higher the render mode’s detail settings, the more triangles are produced, resulting in larger memory requirements and more time to re-emit the light energy onto each triangle’s neighbours. Doubling the number of surfaces in a model actually quadruples the time required for Radiosity processing.
