Title
Local, deformable precomputed radiance transfer
Abstract
Precomputed radiance transfer (PRT) captures realistic lighting effects from distant, low-frequency environmental lighting but has been limited to static models or precomputed sequences. We focus on PRT for local effects such as bumps, wrinkles, or other detailed features, but extend it to arbitrarily deformable models. Our approach applies zonal harmonics (ZH) which approximate spherical functions as sums of circularly symmetric Legendre polynomials around different axes. By spatially varying both the axes and coefficients of these basis functions, we can fit to spatially varying transfer signals. Compared to the spherical harmonic (SH) basis, the ZH basis yields a more compact approximation. More important, it can be trivially rotated whereas SH rotation is expensive and unsuited for dense per-vertex or per-pixel evaluation. This property allows, for the first time, PRT to be mapped onto deforming models which re-orient the local coordinate frame. We generate ZH transfer models by fitting to PRT signals simulated on meshes or simple parametric models for thin membranes and wrinkles. We show how shading with ZH transfer can be significantly accelerated by specializing to a given lighting environment. Finally, we demonstrate real-time rendering results with soft shadows, inter-reflections, and subsurface scatter on deforming models.
Year
DOI
Venue
2005
10.1145/1186822.1073335
ACM Trans. Graph.
Keywords
Field
DocType
spherical function,low frequency,legendre polynomial,spherical harmonics,nonlinear optimization,real time rendering,parametric model,texture mapping,spherical harmonic,texture maps,subsurface scattering
Polygon mesh,Parametric model,Computer graphics (images),Computer science,Legendre polynomials,Spherical harmonics,Basis function,Precomputed Radiance Transfer,Rendering (computer graphics),Geometry,Subsurface scattering
Journal
Volume
Issue
ISSN
24
3
0730-0301
Citations 
PageRank 
References 
67
2.54
25
Authors
3
Name
Order
Citations
PageRank
Peter-Pike Sloan179645.22
Ben Luna2672.54
John Snyder32579172.17