Jaroslav Křivánek

Recent Advances in Light Transport Simulation: Some Theory and a Lot of Practice

SIGGRAPH 2014 Course

Jaroslav Křivánek Charles University in Prague

Alexander Keller NVIDIA

Iliyan Georgiev Solid Angle

Anton S. Kaplanyan Karlsruhe Institute of Technology

Marcos Fajardo Solid Angle

Mark Meyer PIXAR Animation Studios

Jean-Daniel Nahmias PIXAR Animation Studios

Ondřej Karlík Charles University in Prague Render Legion s.r.o.

Juan Canada Next Limit Technologies

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Abstract

We are witnessing a renewed research interest in robust and efficient light transport simulation based on statistical methods. This research effort is propelled by the desire to accurately render general environments with complex materials and light sources, which is often difficult with the industry-standard ad hoc solutions. In addition, it has been recognized that advanced methods, which are able to render many effects in one pass without excessive tweaking, increase artists’ productivity and allow them to focus on their creative work. For this reason, the movie industry is shifting away from approximate rendering solutions towards physically-based rendering methods, which poses new challenges in terms of strict requirements on high image quality and algorithm robustness.

Many of the recent advances in light transport simulation, such as new Markov chain Monte Carlo methods, the robust combination of bidirectional path tracing with photon mapping, or path space filtering are made possible by interpreting light transport as an integral in the space of light paths. However, there is a great deal of confusion among practitioners and researchers alike regarding these path space methods.

The main contribution of the theoretical part of the course is a coherent review of the path integral formulation of light transport and its applications, including the most recent ones. We show that rendering algorithms that may seem complex at first sight, are in fact naturally derived from this general framework. We also show that the path integral framework makes the extension of the surface-based algorithm to volumetric media extremely simple. The course includes an extensive empirical comparison of the various light transport algorithms. A substantial part of the course is then devoted to the application of advanced light transport simulation and path sampling methods in practical rendering tasks in architectural visualization and VFX. ... Extended abstract

Note: This course is an evolution of our 2013 course on light transport. While the original course focused on theoretical aspects, in the updated course we shift our attention toward more practical issues.

Publication & Presentation

Jaroslav Křivánek, Alexander Keller, Iliyan Georgiev, Anton S. Kaplanyan, Marcos Fajardo, Mark Meyer, Jean-Daniel Nahmias, Ondřej Karlík and Juna Canada. 2014. Recent Advances in Light Transport Simulation: Some Theory and a lot of Practice. In ACM SIGGRAPH 2014 Courses (SIGGRAPH '14) ... DOI | BibTeX entry

Presented on Tuesday, 12 August 2014 | 2:00 PM - 5:15 PM in Vancouver Convention Centre, West Building, Rooms 109/110.

Syllabus & Course Notes

Syllabus & course overview (PDF).

Course notes will be posted right after the SIGGRAPH presentations.

Feel free to use any of the slides as long as you acknowledge the slide author as well as this course site.

2:00pm	Introduction & welcome (Křivánek) notes pages | slides
2:05pm	Path integral formulation of light transport (Křivánek) notes pages | slides
2:25pm	Combining bidirectional path tracing and photon mapping (Georgiev) notes pages | slides
2:45pm	Path space filtering (Keller) slides | MCQMC2014 article (The article has been submitted to the proceedings of MCQMC2014, the 11th International Conference on Monte Carlo and Quasi-Monte Carlo Methods in Scientific Computing, http://mcqmc2014.cs.kuleuven.be.)
3:05pm	Comparison of advanced light transport methods (Kaplanyan) notes pages | slides
3:30pm	break
3:45pm	Efficiency = Good importance sampling (Fajardo)
4:05pm	PIXAR's fast lighting preview (Nahmias)
4:25pm	Corona Renderer: It's all about usability (Karlík) notes pages
4:45pm	Advanced light transport in the VFX/archiviz industry (Canada)

Acknowledgements