tions. However due to the lower geometric complex-
ity the absolute values aren’t as high. Our algorithm
performs traversal 1.53x faster than RAH in Cornell,
a signiﬁcant reduction.
Finally for the Sponza scene we see a similar rel-
ative time spent in the traversal of the hierarchy vs
previous scenes. Even though the Sponza scene isn’t
subdivided into separate object meshes, we manage to
slightly outperform RAH at traversal.
6 CONCLUSIONS AND FUTURE
WORK
Our paper described an algorithm to create a Ray-
Space Hierarchy which markedly reduces the inter-
sections, required to ray-trace a scene, due to im-
proved coherency and a shallow BVH.
We achieved our goal of reducing intersections us-
ing a Ray-Space Hierarchy. This technique is orthog-
onal to the use of both Object and Space Hierarchies.
These can be used together to obtain even better re-
sults. Our results show a reduction in computed inter-
sections of 50% for shadow rays and 25% for reﬂec-
tion rays compared to previous state of the art RSHs.
There is room for improvements: Since the hash
determines how rays are sorted, an hierarchy will
improve if we enhance the ray spatial coherency.
We used spherical bounding volumes and a shallow
BVH. In the future we aim to combine our coher-
ent ray hierarchy with a deeper BVH to further de-
screase ray-primitive intersections e.g. (Bradshaw
and O’Sullivan, 2004).
ACKNOWLEDGEMENTS
This work was supported by national funds through
Fundac¸
˜
ao para a Ci
ˆ
encia e Tecnologia (FCT) with ref-
erence UID/CEC/50021/2013.
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