Fast Hardware Construction and Refitting of Quantized Bounding Volume Hierarchies

Timo Viitanen, Matias Koskela, Pekka Jääskeläinen, Kalle Immonen, Jarmo Takala

    Research output: Contribution to journalArticleScientificpeer-review

    1 Citation (Scopus)
    351 Downloads (Pure)


    There is recent interest in GPU architectures designed to accelerate ray tracing, especially on mobile systems with limited memory bandwidth. A promising recent approach is to store and traverse Bounding Volume Hierarchies (BVHs), used to accelerate ray tracing, in low arithmetic precision. However, so far there is no research on refitting or construction of such compressed BVHs, which is necessary for any scenes with dynamic content. We find that in a hardware-accelerated tree update, significant memory traffic and runtime savings are available from streaming, bottom-up compression. Novel algorithmic techniques of modulo encoding and treelet-based compression are proposed to reduce backtracking inherent in bottom-up compression. Together, these techniques reduce backtracking to a small fraction. Compared to a separate top-down compression pass, streaming bottom-up compression with the proposed optimizations saves on average 42% of memory accesses for LBVH construction and 56% for refitting of compressed BVHs, over 16 test scenes. In architectural simulation, the proposed streaming compression reduces LBVH runtime by 20% compared to a single-precision build, and 41% compared to a single-precision build followed by top-down compression. Since memory traffic dominates the energy cost of refitting and LBVH construction, energy consumption is expected to fall by a similar fraction.
    Original languageEnglish
    Pages (from-to)167-178
    Number of pages12
    JournalComputer Graphics Forum
    Issue number4
    Publication statusPublished - 5 Jul 2017
    Publication typeA1 Journal article-refereed

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

    • Computer Graphics and Computer-Aided Design


    Dive into the research topics of 'Fast Hardware Construction and Refitting of Quantized Bounding Volume Hierarchies'. Together they form a unique fingerprint.

    Cite this