Real-Time Photometric Area Light Approximation for Interactive Lighting Design

Information

• Publication Type: Master Thesis
• Workgroup(s)/Project(s):
  • Rendering and Modeling
  • VRVis Competence Center
• Date: February 2019
• Date (Start): April 2017
• Date (End): 7. March 2019
• First Supervisor:
  • Michael Wimmer
  • Christian Luksch

Abstract

Photometric light sources are modeled after real-world luminaires and are used in lighting design to accurately simulate lighting. While an accurate evaluation of their illumination is possible with offline global-illumination algorithms, currently used realtime approximations, which are required for an interactive lighting design work flow, are prone to errors when the light source is close to illuminated objects. This is due to the non-zero dimensionality of photometric lights, which are often area or volume lights. In this thesis, we present a new technique to approximate photometric area lights in real time. This new technique is based on combining two sampling strategies that are currently used in game engines to approximate the illumination from diffuse area lights. Our technique samples the photometric area light with this combined sampling strategy and then computes the illumination with a cubature technique based the Delaunay triangulation. To do this in real time, we implemented our method on the GPU and developed a compact triangle data structure that enables an efficient generation of a Delaunay triangulation. The result of this thesis is a new technique for photometric area lights that creates visually plausible approximations in real time, even if the light source is close to illuminated objects.

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BibTeX

@mastersthesis{PROST-2019-RTPAL,
  title =      "Real-Time Photometric Area Light Approximation for
               Interactive Lighting Design",
  author =     "Lukas Prost",
  year =       "2019",
  abstract =   "Photometric light sources are modeled after real-world
               luminaires and are used in lighting design to accurately
               simulate lighting. While an accurate evaluation of their
               illumination is possible with offline global-illumination
               algorithms, currently used realtime approximations, which
               are required for an interactive lighting design work flow,
               are prone to errors when the light source is close to
               illuminated objects. This is due to the non-zero
               dimensionality of photometric lights, which are often area
               or volume lights. In this thesis, we present a new technique
               to approximate photometric area lights in real time. This
               new technique is based on combining two sampling strategies
               that are currently used in game engines to approximate the
               illumination from diffuse area lights. Our technique samples
               the photometric area light with this combined sampling
               strategy and then computes the illumination with a cubature
               technique based the Delaunay triangulation. To do this in
               real time, we implemented our method on the GPU and
               developed a compact triangle data structure that enables an
               efficient generation of a Delaunay triangulation. The result
               of this thesis is a new technique for photometric area
               lights that creates visually plausible approximations in
               real time, even if the light source is close to illuminated
               objects.",
  month =      feb,
  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",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2019/PROST-2019-RTPAL/",
}