Adaptive Mesh Subdivision for Precomputed Radiance Transfer

Jaroslav Křivánek Sumanta Pattanaik Jiří Žára
Proceedings of Spring Conference on Computer Graphics, pp. 104-109, 2004
In precomputed radiance transfer (PRT), the radiance transfer operator is precomputed on vertices of a mesh. During rendering the transfer operator is combined with illumination to produce global illumination effects at real-time frame rates. However, visible error can be introduced by interpolating the transferred radiance between vertices. We propose to adaptively subdivide meshes with PRT in order to avoid the interpolation error. The mesh density is increased where the transferred radiance can change rapidly and introduce high error. We exploit the fact that the illumination frequency in PRT is bounded and thus we are able to perform the subdivision during the preprocessing phase. This obviates the need for dynamic mesh subdivision at render-time. The adaptive subdivision is guided by an error measure based on the transfer operator.