Updated: 05/13/2019 by Computer Hope
CGI image of a fractured 3D surface with soft shadows created using radiosity. Credit: flickr user fdecomite, CC BY 2.0 (

Radiosity is a technique used in CGI to create images with photorealistic global illumination. It approximates the complex diffusion of light on material surfaces, using an engineering technique called FEM, the "finite element method." The probability of illumination is subdivided into smaller problems, called finite elements, which can be solved algebraically.

Many ray tracers use radiosity, in combination with optical effects such as diffuse reflection, to create soft lights and shadows.

Shadow, Software terms