Recent advances in light transport simulation: Theory & practice

Jaroslav Křivánek, Iliyan Georgiev, Anton Kaplanyan, Juan Cañada
SIGGRAPH 2013 (course)

The advanced rendering methods, covered in this course, can handle scenes with complex specular lighting. The left image was rendered with the vertex connection and merging algorithm [Georgiev et al. 2012]. The image on the right was rendered with Metropolis light transport. Manifold exploration [Jakob and Marschner 2012] mutation strategies were used, extended with path space regularization [Kaplanyan and Dachsbacher 2013] to capture reflected caustics from the external point light source.


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 currently employed solutions. In addition, it has been recognized that advanced Monte Carlo 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 toward 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, or the robust combination of bidirectional path tracing with photon mapping, are made possible by interpreting light transport as an integral over the space of light paths. However, there is a great deal of confusion among practitioners and researchers alike regarding these path space methods.

The goal of this course is twofold. First, we present 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. A significant part of the course is devoted to the application of Markov chain Monte Carlo (MCMC) methods for light transport simulation, such as Metropolis light transport and its variants. We include an extensive empirical comparison of these MCMC methods. The second part of the course discusses practical aspects of applying advanced light transport simulation methods in architectural visualization and VFX tasks.

The course is intended for industry professionals and researchers interested in solidifying their knowledge in physically based rendering as well as learning about the latest developments in the field. Rendering software architects and developers looking for the right global illumination solution for their application will also benefit from the course.

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BibTeX reference

 author = {K{\v{r}}iv{\'a}nek, Jaroslav and Iliyan Georgiev and Anton Kaplanyan and Juan Ca\~nada},
 title = {Recent Advances in Light Transport Simulation: Theory & Practice},
 booktitle = {ACM SIGGRAPH 2013 Courses},
 series = {SIGGRAPH '13},
 year = {2013},
 isbn = {978-1-4503-1678-1},
 location = {Los Angeles, California},
 publisher = {ACM},
 address = {New York, NY, USA},