**Christopher Kulla's Homepage** ![ ](images/chriskulla.jpg width="150px") Hello! This is just a small page to collect various things I've worked on. I am a principal rendering engineer at [Epic Games](https://www.epicgames.com/) working on ray tracing and light transport in [Unreal Engine](https://www.unrealengine.com/). (#) Publications and Talks (##) 2022 * ![ ](images/digipro2022_icon.jpg width="96px" border="1") Puppetering the Pixels: Innovative Animation Tools For Stylized Rendering (Digipro 2022) *Lee Kerley, Joshua Beveridge, Dylan Reid, Dylan Gottlieb, David Allen, Stefan Herz, Christopher Kulla, Stirling Duguid, Doug Smith, Arjun Namdeo, Mike Cole* - [Conference Link](https://digiproconf.org/program/program-6/) - [Official Publisher's Link ](https://dl.acm.org/doi/10.1145/3543664.3543673) - [Preprint ](data/s2022-puppeterring-the-pixels.pdf) (##) 2021 * ![ ](images/moblur-icon.jpg width="96px" border="1") Motion Blur Corner Cases ([Ray Tracing Gems II](https://link.springer.com/book/10.1007/978-1-4842-7185-8)) *Christopher Kulla, [Thiago Ize][thiago]* - [Article ](https://link.springer.com/chapter/10.1007/978-1-4842-7185-8_12) (##) 2020 * ![ ](images/caustics-icon.jpg width="96px" border="1") Adaptive Caustics Rendering in Production with Photon Guiding (EGSR 2020 - Industry Track Paper) *[Alejandro Conty][aconty], Christopher Kulla* - [Preprint ](data/egsr_2020_caustics.pdf) - [Presentation Video](https://www.youtube.com/watch?v=CAa2APz1hUc&t=3116s) (##) 2019 * ![ ](images/s2019-course-icon.jpg width="96px" border="1") [Path Tracing In Production - Part 1: Volumes](https://s2019.siggraph.org/presentation/?id=gensub_286&sess=sess199) (Siggraph 2019 Course) - [Slides ](data/s2019_ptip_volumes.pdf) - [Course Website](https://jo.dreggn.org/path-tracing-in-production/2019/index.html) (##) 2018 * ![ ](images/s2018-panel-icon.jpg width="96px" border="1") [Design and Implementation of Modern Production Renderers](https://s2018.siggraph.org/presentation/?id=gensub_447&sess=sess271) (Siggraph 2018 Panel) - [Slides ](data/siggraph-2018-panel.pdf) * ![ ](images/mon_dj.jpg width="96px" border="1") Sony Pictures Imageworks Arnold (ACM Transactions on Graphics 2018) *Christopher Kulla, [Alejandro Conty][aconty], Clifford Stein, [Larry Gritz][lg]* - [Preprint ](data/2018_tog_spi_arnold.pdf) - [Official Publisher's Link ](https://dl.acm.org/citation.cfm?id=3180495) * ![ ](images/manylight2018_icon.jpg width="96px" border="1") Importance Sampling of Many Lights With Adaptive Tree Splitting (HPG 2018) *[Alejandro Conty][aconty], Christopher Kulla* - [Paper ](data/many-lights-hpg2018.pdf) (##) 2017 * ![ ](images/ptcourse_icon.jpg width="96px" border="1") [Path Tracing in Production](https://jo.dreggn.org/path-tracing-in-production/) (Siggraph 2017 Course) - [Slides ](data/arnold-sony-pictures.pdf) - [Course Website](https://jo.dreggn.org/path-tracing-in-production/2017/index.html) * ![ ](images/volcourse_icon.jpg width="96px" border="1") [Production Volume Rendering](http://graphics.pixar.com/library/ProductionVolumeRendering/index.html) (Siggraph 2017 Course) - [Slides ](data/volume-rendering-techniques.pdf) * ![ ](images/pbscourse_icon.jpg width="96px" border="1") [Physically Based Shading in Theory and Practice](http://blog.selfshadow.com/publications/s2017-shading-course/) (Siggraph 2017 Course) - [Slides ](data/s2017_pbs_imageworks_slides_v2.pdf) - [Sheen model report ](data/s2017_pbs_imageworks_sheen.pdf) * ![ ](images/manylight2017_icon.jpg width="96px" border="1") Importance Sampling of Many Lights With Adaptive Tree Splitting (Siggraph 2017 Talks) *[Alejandro Conty][aconty], Christopher Kulla* - [Talk ](data/importance-sampling-lights-abstract.pdf) - [Slides ](data/importance-sampling-lights-slides.pdf) * ![ ](images/smu_icon.jpg width="96px" border="1") Lighting Up The Smurfs Enchanted Forest (Siggraph 2017 Talks) *Xinling Chen, Christopher Kulla, Lucas Miller, Alan Chen* * [Talk ](data/smurfs-abstract.pdf) (##) 2013 * ![ ](images/woz_icon.jpg width="96px" border="1") Oz the Great and Volumetric (Siggraph 2013 Talks) *[Magnus Wrenninge][magnus], Christopher Kulla, Viktor Lundqvist* - [Talk ](data/oz_volumes.pdf) * ![ ](images/bssrdf_icon.png width="96px" border="1") BSSRDF Importance Sampling (Siggraph 2013 Talks) *Alan King, Christopher Kulla, [Alejandro Conty][aconty], Marcos Fajardo* - [Talk ](data/bssrdf.pdf) - [Slides ](data/bssrdf_slides.pdf) (##) 2012 * ![ ](images/teapots_atmo.jpg width="96px" border="1") Importance Sampling Techniques for Path Tracing in Participating Media (EGSR 2012) *Christopher Kulla, Marcos Fajardo* - [Paper ](data/egsr_2012_volume_paper.pdf) - [Slides ](data/egsr_2012_volume_talk.pdf) (##) 2011 * ![ ](images/equiang_icon.jpg width="96px" border="1") Importance Sampling of Area Lights in Participating Media (Siggraph 2011 Talks) *Christopher Kulla, Marcos Fajardo* - [Talk ](data/sketch01_importance_sampling_v2.pdf) - [Supplemental ](data/sketch01_importance_sampling_supp_v2.pdf) - [Slides ](data/sketch01_importance_sampling_talk_v3.pdf) * ![ ](images/decoupled_icon.jpg width="96px" border="1") Decoupled Ray Marching of Heterogeneous Participating Media (Siggraph 2011 Talks) *Christopher Kulla* - [Talk ](data/sketch02_heterogeneous_v2.pdf) - [Slides ](data/sketch02_heterogeneous_talk_v2.pdf) (##) 2010 * ![ ](images/osl_icon.png width="96px" border="1") Open Shading Language (Siggraph 2010 Talks) *[Larry Gritz][lg], Clifford Stein, Christopher Kulla, [Alejandro Conty][aconty]* - [Talk ](data/osl_sketch.pdf) (##) 2003 * ![ ](images/npr-paint-icon.jpg width="96px" border="1") Using Texture Synthesis for Non-Photorealistic Shading from Paint Samples (Pacific Graphics 2003) *Christopher Kulla, James Tucek, [Reynold Bailey](https://www.cs.rit.edu/~rjb/), [Cindy Grimm](http://web.engr.oregonstate.edu/~grimmc/)* - [Paper ](data/npr-paint-2003.pdf) [aconty]: http://www.aconty.com/ [magnus]: http://magnuswrenninge.com/ [lg]: http://www.larrygritz.com/ [thiago]: http://www.sci.utah.edu/~thiago/ (#) Personal Projects [Sunflow](http://sunflow.sourceforge.net/): An open source rendering system for photo-realistic image synthesis. [Buddhabrot Fractal Renderer](http://www.flickr.com/photos/fpsunflower/sets/72157618708053097/) [Tiny OpenEXR output](https://gist.github.com/fpsunflower/e5c99116ff94114d1cbe) [Tiny PNG output](https://gist.github.com/fpsunflower/a79b06e92968465397d4) [Tiny bitmap font rendering](https://gist.github.com/fpsunflower/7e6311c9580409c115a0) [Tiny float to ascii conversion](https://gist.github.com/fpsunflower/c98f8b6099088c3b8bf630ee3d6b773d) (#) Short Bio Christopher Kulla is a principal software engineer at Epic Games where he focuses on ray tracing and light transport. He previously worked at Sony Picture Imageworks on the in-house branch of the Arnold renderer for 13 years, making contributions to ray-tracing kernels, sampling techniques and volume rendering. In 2017 he was recognized with a Scientific and Engineering Award from the Academy of Motion Picture Arts and Sciences for his work on the Arnold renderer. (#) Other Links [Github](https://github.com/fpsunflower/) [Shadertoy](https://www.shadertoy.com/user/fpsunflower) [LinkedIn](https://www.linkedin.com/in/ckulla/) [Google Scholar](https://scholar.google.com/citations?user=HleuowoAAAAJ)