TRAVERSING A BVH CUT TO EXPLOIT RAY COHERENCE

R. Torres, P. J. Martín, A. Gavilanes

2011

Abstract

In this paper we study how to deal with the ray incoherence that naturally arises in path tracing-based systems. We introduce the notion of BVH Cut to split the tree into a forest of disjoint subtrees. We will use it to filter the rays that are successively generated by the path tracing algorithm. Each subtree is then traversed by its corresponding group of rays. Despite the overload of filtering all the rays each time, a significant profit is achieved. Nevertheless, constructing a BVH cut is a challenging task, because it can lead to a huge amount of work if the same rays belongs to many groups. Thus, we present two kind of building heuristics: structural heuristics that characterizes the root of a subtree by a property (the node’s depth or the surface area of its bounding volume in this paper), and optimization heuristics that are based on the Simulated Annealing method. The performance of traversing the cuts so built has been experimentally analyzed over four usual scenes, using two popular implementations of the subtree traversal (persistent while-while / persistent packet). The results show a relevant saving time w.r.t. the classic BVH traversal, that grows as the ray incoherence increases. The best saving ranges from 32.0% / 40.9% for structural heuristics, to 32.0% / 51.7% for cuts built with Simulated Annealing.

Paper Citation

in Harvard Style

Torres R., J. Martín P. and Gavilanes A. (2011). TRAVERSING A BVH CUT TO EXPLOIT RAY COHERENCE . In Proceedings of the International Conference on Computer Graphics Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2011) ISBN 978-989-8425-45-4, pages 140-150. DOI: 10.5220/0003363401400150

in Bibtex Style

@conference{grapp11,
author={R. Torres and P. J. Martín and A. Gavilanes},
title={TRAVERSING A BVH CUT TO EXPLOIT RAY COHERENCE},
booktitle={Proceedings of the International Conference on Computer Graphics Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2011)},
year={2011},
pages={140-150},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0003363401400150},
isbn={978-989-8425-45-4},
}

in EndNote Style

TY - CONF
JO - Proceedings of the International Conference on Computer Graphics Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2011)
TI - TRAVERSING A BVH CUT TO EXPLOIT RAY COHERENCE
SN - 978-989-8425-45-4
AU - Torres R.
AU - J. Martín P.
AU - Gavilanes A.
PY - 2011
SP - 140
EP - 150
DO - 10.5220/0003363401400150