A Virtual Light Field for Propagation and Walkthrough of Globally Illuminated Scenes

Pankaj Khanna, Mel Slater, Jesper Mortensen, Insu Yu

Abstract:
This paper describes an algorithm that provides real-time walkthrough for globally illuminated scenes comprising of ideal diffuse and specular polygonal surfaces. A type of light field data structure is used for propagating radiance outward from light emitters through the scene and accounts for all L(S|D)* light paths. The light field employed is constructed by choosing a regular point subdivision over a hemisphere, to give a set of directions, and then corresponding to each direction creating a rectangular grid of parallel rays. Each rectangular grid of rays, called a ‘parallel subfield’ is further subdivided into rectangular tiles, such that each tile references a sequence of 2D “images” containing colour values corresponding to the outgoing radiances of surfaces intersected by the rays belonging to that tile. Following propagation, this structure is used for final image rendering. Propagation times are currently very long and the memory requirements high. This algorithm, however, offers a global illumination solution for real-time walkthrough even on a single processor.

Media:
The paper (1.9MB)