Real-Time Global Illumination for Voxel Worlds

Information

• Publication Type: Bachelor Thesis
• Workgroup(s)/Project(s):
  • Rendering and Modeling
• Date: October 2025
• Date (Start): 18. November 2024
• Date (End): 13. October 2025
• Matrikelnummer: 12121278
• First Supervisor: Michael Wimmer
• Second Supervisor: Annalena Ulschmid
• Keywords: Real-Time Rendering, Voxels, Global Illumination, Ray Tracing

Abstract

Achieving realistic real-time rendering of 3D worlds using path tracing remains a significant challenge due to the high sample count required for noise-free images. With voxel-worlds there are some opportunities for optimizations from its unique geometric structure. Typically, real-time applications are constrained to only a few samples per pixel, requiring additional processing to result in a noise-free image. Traditional solutions attempt to address this issue through spatial and temporal reuse of samples or other image data, but implementations frequently introduce undesirable artifacts such as blurring, ghosting, or flickering. In voxel worlds this is especially undesireable because of its sharp geometric features. In this work, we explore a specialized rendering pipeline for voxel-based worlds. We adapt existing techniques to voxel geometry and use a different approach for temporal reuse in order to minimize image artifacts. We begin by generating a low-sample image using path tracing, which is then refined using temporal and spatial resampling. A simple denoiser optimized for preserving details is then applied to remove most of the noise. As a last step, our specialized approach to Temporal Anti-Aliasing (TAA) is applied, which is a central contribution of our pipeline as it removes almost all common artifacts. To evaluate our approach, we conduct a series of qualitative and quantitative experiments. Visual comparisons against standard techniques show an improvement in image clarity. Performance benchmarks demonstrate that our pipeline operates within real-time constraints on modern GPUs, validating its practical applicability for interactive voxel-based applications such as video games. By combining sample refinement adapted to voxel words with lightweight denoising and a data-driven TAA strategy, our method achieves realistic real-time rendering of voxel environments using path tracing with minimal artifacts.

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BibTeX

@bachelorsthesis{ott-rgi,
  title =      "Real-Time Global Illumination for Voxel Worlds",
  author =     "Marvin Ott",
  year =       "2025",
  abstract =   "Achieving realistic real-time rendering of 3D worlds using
               path tracing remains a significant challenge due to the high
               sample count required for noise-free images. With
               voxel-worlds there are some opportunities for optimizations
               from its unique geometric structure. Typically, real-time
               applications are constrained to only a few samples per
               pixel, requiring additional processing to result in a
               noise-free image. Traditional solutions attempt to address
               this issue through spatial and temporal reuse of samples or
               other image data, but implementations frequently introduce
               undesirable artifacts such as blurring, ghosting, or
               flickering. In voxel worlds this is especially undesireable
               because of its sharp geometric features. In this work, we
               explore a specialized rendering pipeline for voxel-based
               worlds. We adapt existing techniques to voxel geometry and
               use a different approach for temporal reuse in order to
               minimize image artifacts. We begin by generating a
               low-sample image using path tracing, which is then refined
               using temporal and spatial resampling. A simple denoiser
               optimized for preserving details is then applied to remove
               most of the noise. As a last step, our specialized approach
               to Temporal Anti-Aliasing (TAA) is applied, which is a
               central contribution of our pipeline as it removes almost
               all common artifacts. To evaluate our approach, we conduct a
               series of qualitative and quantitative experiments. Visual
               comparisons against standard techniques show an improvement
               in image clarity. Performance benchmarks demonstrate that
               our pipeline operates within real-time constraints on modern
               GPUs, validating its practical applicability for interactive
               voxel-based applications such as video games. By combining
               sample refinement adapted to voxel words with lightweight
               denoising and a data-driven TAA strategy, our method
               achieves realistic real-time rendering of voxel environments
               using path tracing with minimal artifacts.",
  month =      oct,
  address =    "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria",
  school =     "Research Unit of Computer Graphics, Institute of Visual
               Computing and Human-Centered Technology, Faculty of
               Informatics, TU Wien ",
  keywords =   "Real-Time Rendering, Voxels, Global Illumination, Ray
               Tracing",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2025/ott-rgi/",
}