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Wilhem Barbier

@wbrbr.bsky.social
129 followers 337 following 33 posts

Graphics engineer, currently working on Marmoset Toolbag. Previously: PhD @ IRIT, R&D intern @ Adobe, Unity

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Wilhem Barbier @wbrbr.bsky.social · 23/06/2025
As a result, our method consistently reduces the build time although this comes at the cost of an increase in tracing time. We show that this tradeoff is worth it for real-time raytracing of complex dynamic scenes since rebuilds are particularly expensive. Check out the paper for more details!
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Wilhem Barbier @wbrbr.bsky.social · 23/06/2025
In this paper we focus on maximizing build speed by removing this additional traversal. To do so we introduce a bottom-up collapsing algorithm, which we integrate into an existing high-performance BVH2 builder to obtain a fast wide BVH construction algorithm.
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Wilhem Barbier @wbrbr.bsky.social · 23/06/2025
However most of the GPU BVH construction litterature focuses on binary hierarchies. A notable exception is H-PLOC by Benthin et al which uses a binary builder and a separate top-down collapsing step to convert the binary BVH into a wide BVH.
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Wilhem Barbier @wbrbr.bsky.social · 23/06/2025
The standard acceleration structure for ray-tracing is the wide BVH, and fast GPU construction of these hierarchies is a key challenge for realtime raytracing. This is especially important for complex dynamic scenes where BVH rebuilds are a major bottleneck. Example: Flooded Sponza by Intel.
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Wilhem Barbier @wbrbr.bsky.social · 30/05/2025
Back to fiddling with my Vulkan path tracer
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Wilhem Barbier @wbrbr.bsky.social · 07/05/2025
These pruned trees enable efficient evaluation of the SDF for rendering or discretization, resulting in >100x speedups for complex scenes compared to brute-force evaluation. Come to my talk next week for more details, or read the paper here: wbrbr.org/publications...
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Wilhem Barbier @wbrbr.bsky.social · 07/05/2025
Our algorithm takes as input an analytical SDF represented as a tree of smooth booleans and a 3D region of space, and computes a much smaller pruned tree equivalent within the region. This procedure is simple and efficient, using the Lipschitz prop. of the SDFs instead of costly interval arithmetic
Overview of our method. Left: a shape is described by a smooth CSG tree. Middle: the scene is divided into a grid, and we computed a pruned tree for every cell. Right: these pruned tree are much smaller than the input tree, and enable faster SDF evaluation for sphere tracing or SDF discretization.
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Wilhem Barbier @wbrbr.bsky.social · 07/05/2025
I am proud to announce our Eurographics 2025 paper "Lipschitz Pruning: Hierarchical Simplification of Primitive-Based SDFs"! With Mathieu Sanchez (joint first author), @axelparis.bluesky.social, @elie-michel.bsky.social, Thibaud Lambert, @tamyboubekeur.bsky.social, Mathias Paulin and Théo Thonat.
Left: an input CSG tree and a much smaller pruned tree computed using our method.
Right: a rendered scene showing the number of active nodes per cell. Our method reduces the active nodes to less than 20 from the initial 6023 nodes of the input tree.
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Wilhem Barbier @wbrbr.bsky.social · 27/10/2024
Weekend project: a simple SPH fluid simulator. It's clearly not very good yet, but it's starting to look like something! Fluids are fun
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