In Proceedings of Eurographics Symposium on Rendering
Illumination-Aware Spatial Subdivision for Path Guiding
Path tracing is ubiquitous in production rendering and path guiding has established itself as a powerful approach to mitigate its failure cases. Several widely used methods partition the scene using a k-d tree and store a directional guiding distribution per cell for importance sampling. While a lot of research has improved the guiding distributions, the decision when to split the k-d tree still relies on a simple sample count threshold. We propose a method to adapt the k-d tree depending on the variation in the illumination. To this end, we use lookahead cells, i.e. multiple additional levels of k-d tree cells that do not store a guiding distribution. Instead, they store compact characterizations of the light field, which we call signatures. Specifically, we use the mean radiance and radiance-weighted mean direction. We model the uncertainty in these signatures probabilistically to derive split criteria that split k-d tree cells when we are confident that one of their lookahead cells differs substantially. As a result, we make existing guiding methods allocate computational and storage resources more efficiently, using small cells in regions with rapidly varying illumination whilst sharing data for uniformly lit regions.
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@inproceedings{bib:zheng:2026,
author = { Zheng, Fengshi and Peters, Christoph and Herholz, Sebastian and Manzi, Marco and Eisemann, Elmar },
title = { Illumination-Aware Spatial Subdivision for Path Guiding },
booktitle = { In Proceedings of Eurographics Symposium on Rendering },
editors = { Gkioulekas, Ioannis and Jarabo, Adrian },
year = { 2026 },
publisher = { The Eurographics Association },
doi = { 10.2312/sr.20261000 },
url = { https://publications.graphics.tudelft.nl/papers/857 },
}