What Does Radiosity Mean?
Radiosity is a term for a particular algorithm set that helps to mimic the diffusion of light or natural illumination processes. It is a general improvement on computer graphics rendering which was previously done with direct illumination algorithms.
Techopedia Explains Radiosity
What radiosity does is essentially provide a more sophisticated illumination design in graphics rendering that reflects blurred edges, shadows and what is called a “shadow umbra.” This effect is visible in the shading and gradations of flat illuminated spaces where light gradually filters out and where light is radiated in elaborate ways with blurred edging and other features. This enhances what developers are able to do in computer graphics without manual adjustment.