Computer Graphics
Research Scientist | Software Engineer

Research Areas:

Note: I get asked this often, but no, this is not a photo of me, it's a completely computer generated rendering of a Canadian actor. See this paper for details.

Appearance Modeling

Describing the appearance real physical materials with new models and algorithms.

Photorealistic Image Synthesis

Developing new techniques to generate images indistinguishable from what we see around us in the natural world.

Efficient Light Transport Models

Developing efficient, practical, and accurate models for light transport in complex materials.

Measurement Techniques

Designing methods for accurate measurement of real world material characteristics for use in various scientific fields.


I was always fascinated by the appearance of the world, and later researched and created tools for acquiring appearance characteristics as well as more general light transport and rendering methods. In 2012, I joined Google, and have worked on everything from Google Earth, to Cardboard, Virtual Reality, and Daydream. Over the years I've built small systems, tools and also rolled out Google-scale infrastructure, and enabled research in journales such as Nature. I've led teams as small as a handful and as large as many dozens. At the moment, I direct the engineering of DeepMind's Science group in London, UK.

Before Google, I ran my own shop called Leolux that created custom rendering software and tools for the realistic rendering of biological materials. Before that, I was a Postdoctoral Researcher in the Computer Graphics group at Columbia University, with Professor Ravi Ramamoorthi, from Fall 2007 through Fall 2009. Before joining the lab at Columbia, I was a postdoc in the Graphics group of the University of California, San Diego, where I also did my Ph.D. under Professor Henrik Wann Jensen.


A Practical Appearance Model for Dynamic Facial Color
ACM Trans. Graph. 29:6:1-141:1-10 (Proceedings of SIGGRAPH Asia 2010), 2010

Adaptive Wavelet Rendering
ACM Trans. Graph. 28:5:1-140:1-12 (Proceedings of SIGGRAPH Asia 2009), 2009

An Empirical BSSRDF Model
ACM Trans. Graph. 28:3:1-30:1--10 (Proceedings of SIGGRAPH 2009), 2009

A Layered, Heterogeneous Reflectance Model for Acquiring and Rendering Human Skin
ACM Trans. Graph. 27:5:140:1-12 (Proceedings of SIGGRAPH Asia 2008), 2008

Radiance Caching for Participating Media
ACM Trans. Graphic., 27(1):1-11, 2008

Rendering Translucent Materials Using Photon Diffusion
In Rendering Techniques (Proceedings of the Eurographics Symposium on Rendering), 2007, 234--251, 2007.

Radiance Caching for Participating Media
In ACM SIGGRAPH Sketches and Applications, 2007

A Spectral BSSRDF for Shading Human Skin
In Rendering Techniques (Proceedings of the Eurographics Symposium on Rendering), pages 409--417, 2006

Acquiring Scattering Properties of Participating Media by Dilution
ACM Trans. Graphic. (Proceedings of ACM SIGGRAPH 2006), 25:1003--1012, 2006

Analysis of Human Faces using a Measurement-Based Skin Reflectance Model
ACM Trans. Graphic. (Proceedings of ACM SIGGRAPH 2006), 25:1013--1024, 2006

A Spectral Shading Model for Human Skin
In ACM SIGGRAPH Sketches and Applications, 2006

Light Diffusion in Multi-Layered Translucent Materials
ACM Trans. Graphic. (Proceedings of ACM SIGGRAPH 2005), 24(3):1032--1039, 2005

Faster GPU Computations Using Adaptive Refinement
In ACM SIGGRAPH Sketches and Applications, 2004

Photon Mapping on Programmable Graphics Hardware
In Proceedings of Graphics Hardware, 2003
Winner: Best Paper