44-Issue 8

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https://diglib.eg.org/handle/10.2312/3607201

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Browsing 44-Issue 8 by Subject "Massively parallel algorithms"

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    DOBB-BVH: Efficient Ray Traversal by Transforming Wide BVHs into Oriented Bounding Box Trees using Discrete Rotations
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Kern, Michael A.; Galvan, Alain; Oldcorn, David R.; Skinner, Daniel; Mehalwal, Rohan; Lozano, Leo Reyes; Chajdas, Matthäus G.; Knoll, Aaron; Peters, Christoph
    Oriented bounding box (OBB) bounding volume hierarchies offer a more precise fit than axis-aligned bounding box hierarchies in scenarios with thin elongated and arbitrarily rotated geometry, enhancing intersection test performance in ray tracing. However, determining optimally oriented bounding boxes can be computationally expensive and have high memory requirements. Recent research has shown that pre-built hierarchies can be efficiently converted to OBB hierarchies on the GPU in a bottom-up pass, yielding significant ray tracing traversal improvements. In this paper, we introduce a novel OBB construction technique where all internal node children share a consistent OBB transform, chosen from a fixed set of discrete quantized rotations. This allows for efficient encoding and reduces the computational complexity of OBB transformations. We further extend our approach to hierarchies with multiple children per node by leveraging Discrete Orientation Polytopes (k-DOPs), demonstrating improvements in traversal performance while limiting the build time impact for real-time applications. Our method is applied as a post-processing step, integrating seamlessly into existing hierarchy construction pipelines. Despite a 12.6% increase in build time, our experimental results demonstrate an average improvement of 18.5% in primary, 32.4% in secondary rays, and maximum gain of 65% in ray intersection performance, highlighting its potential for advancing real-time applications.
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    Fused Collapsing for Wide BVH Construction
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Barbier, Wilhem; Paulin, Mathias; Knoll, Aaron; Peters, Christoph
    We propose a novel approach for constructing wide bounding volume hierarchies on the GPU by integrating a simple bottom-up collapsing procedure within an existing binary bottom-up BVH builder. Our approach directly constructs a wide BVH without traversing a temporary binary BVH as done by previous approaches and achieves 1.4−1.6× lower build times. We demonstrate the ability of our algorithm to output compressed wide BVHs using existing compressed representations. We analyze the impact of our method on software raytracing performance and show that it reduces the overall frame time on complex dynamic scenes where rebuilding the BVH every frame is the limiting factor on rendering performance.
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    UBVH: Unified Bounding Volume and Scene Geometry Representation for Ray Tracing
    (The Eurographics Association and John Wiley & Sons Ltd., 2025) Kácerik, Martin; Bittner, Jirí; Knoll, Aaron; Peters, Christoph
    Bounding volume hierarchies (BVHs) are currently the most common data structure used to accelerate ray tracing. The existing BVH methods distinguish between the bounding volume representation associated with the interior BVH nodes and the scene geometry representation associated with leaf nodes. We propose a new method that unifies the representation of bounding volumes and triangular scene geometry. Our unified representation builds on skewed oriented bounding boxes (SOBB) that yield tight bounds for interior nodes and precise representation for triangles in the leaf nodes. This innovation allows to streamline the conventional massively parallel BVH traversal, as there is no need to switch between testing for ray intersection in interior nodes and leaf nodes. The results show that the proposed method accelerates ray tracing of incoherent rays between 1.2x-11.8x over the AABB BVH, 1.4x-4.2x over the 14-DOP BVH, 1.1x-2.0x over the OBB BVH, and by 1.1x-1.7x over the SOBB BVH.