Papers by Leonid Pekelis


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A Data-Driven Light Scattering Model for Hair

Leonid Pekelis, Christophe Hery, Ryusuke Villemin, Junyi Ling
May 2015

We present an implementation of the [Marschner et al. 2003] model for importance sampling light reflected from hair. The implemen- tation makes use of a version of Adaptive Importance Sampling (AIS), specialized to fit easily sampled distributions to BCSDFs. Our model is novel among importance sampling implementations in that it ... more

Paper (PDF)

Additional materials: [hairlock_eccentricity_100.mov], [hairlock_eccentricity_085.mov]

Available as Pixar Technical Memo #15-02


A statistical framework for comparing importance sampling methods, and an application to rectangular lights

Leonid Pekelis, Christophe Hery
February 2014

Importance sampling methods for ray tracing are numerous. One reason is due to the lack of a robust, quantitative method for comparison. This tech memo takes strides to provide a framework for comparing sampling methods on fair ground. We define a simple, mathematical notion of strictly preferring one method to ... more

Paper (PDF)

Available as Pixar Technical Memo #14-01