Abstract de la publi numéro 3888
Physically based rendering needs numerical models from real measurements,
or analytical models from material definitions, of the Bi-directional
Reflectance Distribution Function (BRDF).
However, measured BRDF data sets are too large and provide no functionalities to
be practically used in Monte Carlo path tracing algorithms. In this paper,
we present a wavelet based generic BRDF model suitable for both physical
analysis and path tracing. The model is based on the separation
of spectral and geometrical aspect of the BRDF and allows a compact and
efficient representation of isotropic, anisotropic and/or spectral BRDFs.
After a brief survey of BRDF and wavelet theory, we present our software
architecture for generic wavelet transform and how to use it to model BRDFs.
Then, modelling results are presented on real and virtual BRDF measurements.
Finally, we show how to exploit the multi-resolution property of the wavelet
encoding to reduce the variance by importance sampling in a path tracing algorithm.