Order by: Date | Author | Title | Index of all authors | Index of Pixar Technical Memos

Correlated Multi-Jittered SamplingAndrew KenslerMarch 2013We present a new technique for generating sets of stratified samples on the unit square. Though based on jittering, this method is competitive with low-discrepancy quasi-Monte Carlo sequences while avoiding some of the structured artifacts to which they are prone. An efficient implementation is provided that allows repeatable, ... more Paper (PDF) Available as Pixar Technical Memo #13-01 | |

Building an Orthonormal Basis, RevisitedTom Duff, James Burgess, Per Christensen, Christophe Hery, Andrew Kensler, Max Liani, Ryusuke VilleminMarch 2017Frisvad [2012b] describes a widely-used computational method for augmenting a given single unit vector with two other vectors to produce an orthonormal frame in three dimensions, a useful operation for any physically based renderer. The implementation has a precision problem: as the z component of the input vector approaches -1, floating point cancellation causes ... more Paper (PDF) | |

Progressive Multi-Jittered Sample SequencesPer Christensen, Andrew Kensler, Charlie KilpatrickJuly 2018We introduce three new families of stochastic algorithms to generate progressive 2D sample point sequences. This opens a general framework that researchers and practitioners may find useful when developing future sample sequences. Our best sequences have the same low sampling error as the best known sequence (a particular randomization of ... more Paper (PDF) Additional materials: [pmj_slides.pdf], [pmj_suppl.pdf]Computer Graphics Forum (Proceedings of the Eurographics Symposium on Rendering 2018) | |

RenderMan: An Advanced Path Tracing Architecture for Movie RenderingPer Christensen, Julian Fong, Jonathan Shade, Wayne Wooten, Brenden Schubert, Andrew Kensler, Stephen Friedman, Charlie Kilpatrick, Cliff Ramshaw, Marc Bannister, Brenton Rayner, Jonathan Brouillat, Max LianiJuly 2018Pixar's RenderMan renderer is used to render all of Pixar's films, and by many film studios to render visual effects for live-action movies. RenderMan started as a scanline renderer based on the Reyes algorithm, and was extended over the years with ray tracing and several global illumination algorithms. This paper describes the modern version of ... more Paper (PDF) | |

Orthogonal Array Sampling for Monte Carlo RenderingWojciech Jarosz, Afnan Enayet, Andrew Kensler, Charlie Kilpatrick, Per ChristensenJuly 2019We generalize N-rooks, jittered, and (correlated) multi-jittered sampling to higher dimensions by importing and improving upon a class of techniques called orthogonal arrays from the statistics literature. Renderers typically combine or "pad" a collection of lower-dimensional (e.g. 2D and 1D) stratified patterns to form higher-dimensional samples for integration. ... more Paper (PDF) Additional materials: [images.tar.xz], [supplemental.pdf] |