Skip to main content

Research Repository

Advanced Search

Emulating Foveated Path Tracing

Polychronakis, Andrew; Koulieris, George Alex; Mania, Katerina; Boulic, Ronan; Hoyet, Ludovic; Singh, Karan; Rohmer, Damien

Emulating Foveated Path Tracing Thumbnail


Andrew Polychronakis

Katerina Mania

Ronan Boulic

Ludovic Hoyet

Karan Singh

Damien Rohmer


At full resolution, path tracing cannot be deployed in real-time based on current graphics hardware due to slow convergence times and noisy outputs, despite recent advances in denoisers. In this work, we develop a perceptual sandbox emulating a foveated path tracer to determine the eccentricity angle thresholds that enable imperceptible foveated path tracing. In a foveated path tracer the number of rays fired can be decreased, and thus performance can be increased. For this study, due to current hardware limitations prohibiting real-time path-tracing for multiple samples-per-pixel, we pre-render image buffers and emulate foveated rendering as a post-process by selectively blending the pre-rendered content, driven by an eye tracker capturing eye motion. We then perform three experiments to estimate conservative thresholds of eccentricity boundaries for which image manipulations are imperceptible. Contrary to our expectation of a single threshold across the three experiments, our results indicated three different average thresholds, one for each experiment. We hypothesise that this is due to the dissimilarity of the methodologies, i.e., A-B testing vs sequential presentation vs custom adjustment of eccentricities affecting the perceptibility of peripheral blur among others. We estimate, for the first time for path tracing, specific thresholds of eccentricity that limit any perceptual repercussions whilst maintaining high performance. We perform an analysis to determine potential computational complexity reductions due to foveation in path tracing. Our analysis shows a significant boost in path-tracing performance (≥ 2x − 3x) using our foveated rendering method as a result of the reduction in the primary rays.


Polychronakis, A., Koulieris, G. A., Mania, K., Boulic, R., Hoyet, L., Singh, K., & Rohmer, D. (2021). Emulating Foveated Path Tracing. In MIG '21: Proceedings of the 14th ACM SIGGRAPH Conference on Motion, Interaction and Games.

Conference Name ACM SIGGRAPH Conference on Motion, Interaction and Games
Conference Location Virtual
Start Date Nov 10, 2021
End Date Nov 12, 2021
Acceptance Date Sep 7, 2021
Online Publication Date Nov 10, 2021
Publication Date Nov 10, 2021
Deposit Date Oct 18, 2021
Publicly Available Date Nov 13, 2022
Book Title MIG '21: Proceedings of the 14th ACM SIGGRAPH Conference on Motion, Interaction and Games


Accepted Conference Proceeding (6.4 Mb)

Copyright Statement
© ACM 2021. This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in MIG '21: Proceedings of the 14th ACM SIGGRAPH Conference on Motion, Interaction and Games,

You might also like

Downloadable Citations