Browsing by Author "Grosch, Thorsten"

Now showing 1 - 6 of 6
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    Fast and Dynamic Construction of Bounding Volume Hierarchies Based on Loose Octrees
    (The Eurographics Association, 2018) Gu, Feng; Jendersie, Johannes; Grosch, Thorsten; Beck, Fabian and Dachsbacher, Carsten and Sadlo, Filip
    Many fast methods for constructing BVHs on the GPU only use the centroids of primitive bounding boxes and ignore the actual spatial extent of each primitive. We present a fast new way and a memory-efficient implementation to build a BVH from a loose octree for real-time ray tracing on fully dynamic scenes. Our memory-efficient implementation is an in-place method and generalizes the state-of-the-art parallel construction for LBVH to build the BVH from nodes of different levels.
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    Microfacet Model Regularization for Robust Light Transport
    (The Eurographics Association and John Wiley & Sons Ltd., 2019) Jendersie, Johannes; Grosch, Thorsten; Boubekeur, Tamy and Sen, Pradeep
    Today, Monte Carlo light transport algorithms are used in many applications to render realistic images. Depending on the complexity of the used methods, several light effects can or cannot be found by the sampling process. Especially, specular and smooth glossy surfaces often lead to high noise and missing light effects. Path space regularization provides a solution, improving any sampling algorithm, by modifying the material evaluation code. Previously, Kaplanyan and Dachsbacher [KD13] introduced the concept for pure specular interactions. We extend this idea to the commonly used microfacet models by manipulating the roughness parameter prior to the evaluation. We also show that this kind of regularization requires a change in the MIS weight computation and provide the solution. Finally, we propose two heuristics to adaptively reduce the introduced bias. Using our method, many complex light effects are reproduced and the fidelity of smooth objects is increased. Additionally, if a path was sampleable before, the variance is partially reduced.
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    Multi-Layer Alpha Tracing
    (The Eurographics Association, 2020) Brüll, Felix; Grosch, Thorsten; Krüger, Jens and Niessner, Matthias and Stückler, Jörg
    Rendering many transparent surfaces in real-time is still an open problem. We introduce two techniques for fast transparency rendering with ray tracing hardware, one being exact and the other being approximate but of high quality. Our approximate technique is called Multi-Layer Alpha Tracing, operates in bounded memory and is up to 60% faster than naive ray traversal. It outperforms existing rasterization techniques in terms of image quality and performance while maintaining a small memory footprint. It can also be used to accelerate ray tracing of transparent objects for the reflected rays.
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    Relaxed Parallel Priority Queue with Filter Levels for Parallel Mesh Decimation
    (The Eurographics Association, 2022) Stümmel, Marvin; Brüll, Felix; Grosch, Thorsten; Bender, Jan; Botsch, Mario; Keim, Daniel A.
    We propose a novel implementation of a parallel priority queue in the context of multithreaded mesh decimation. Previous parallel priority queues either have a major bottleneck when extracting nodes, cannot guarantee reasonable node quality for the extracted nodes, or cannot be used for mesh decimation. Our data structure allows the extraction of multiple high-priority elements at the same time. For this, we relax the requirement of returning the highest priority element to returning an element that belongs to the top k elements. We demonstrate its use in the context of parallel mesh decimation and show that our decimated mesh is almost indistinguishable from an optimally decimated mesh while being 2 to 2.6 times faster than a naive parallel priority queue implementation.
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    Stenciled Volumetric Ambient Occlusion
    (The Eurographics Association, 2022) Brüll, Felix; Kern, René; Grosch, Thorsten; Ghosh, Abhijeet; Wei, Li-Yi
    Screen-space Ambient Occlusion (AO) is commonly used in games to calculate the exposure of each pixel to ambient lighting with the help of a depth buffer. Due to its screen-space nature, it suffers from several artifacts if depth information is missing. Stochastic-Depth AO [VSE21] was introduced to minimize the probability of missing depth information, however, rendering a full stochastic depth map can be very expensive. We introduce a novel rendering pipeline for AO that divides the AO pass into two phases, which allows us to create a stochastic depth map for only a subset of pixels, in order to decrease the rendering time drastically. We also introduce a variant that replaces the stochastic depth map with ray tracing that has competitive performance. Our AO variants are based on Volumetric AO [LS10], which produces similar effects compared to the commonly used horizon-based AO [BSD08], but requires less texture samples to produce good results.
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    VMV 2023: Frontmatter
    (The Eurographics Association, 2023) Guthe, Michael; Grosch, Thorsten; Guthe, Michael; Grosch, Thorsten