Face Cluster Radiosity

Andrew J. Willmott, Paul S. Heckbert, Michael Garland

Eurographics Workshop on Rendering, June '99

(13 pages.)


An algorithm for simulating diffuse interreflection in complex three dimensional scenes is described. It combines techniques from hierarchical radiosity and multiresolution modelling. A new face clustering technique for automatically partitioning polygonal models is used. The face clusters produced group adjacent triangles with similar normal vectors. They are used during radiosity solution to represent the light reflected by a complex object at multiple levels of detail. Also, the radiosity method is reformulated in terms of vector irradiance and power. Together, face clustering and the vector formulation of radiosity permit large savings. Excessively fine levels of detail are not accessed by the algorithm during the bulk of the solution phase, greatly reducing its memory requirements relative to previous methods. Consequently, the costliest steps in the simulation can be made sub-linear in scene complexity. Using this algorithm, radiosity simulations on scenes of one million input polygons can be computed on a standard workstation.

The paper is online in the following formats:

The workshop talk is also online.

Note: This work has since been expanded on, with particular attention paid to developing bounds for radiosity transfer, and the analysis of the role of intra-cluster visibility in our method. Full details are available in Andrew's PhD thesis, which is available online, along with source code both for creating face cluster hierarchies and performing face cluster radiosity.

Please send any comments or suggestions to us at ajw@cs.cmu.edu, ph@cs.cmu.edu, garland@cs.cmu.edu.