A practical guide to global illumination using ray tracing and photon mapping

  • Authors:

  • Henrik Wann Jensen

  • Affiliations:

  • University of California, San Diego

  • Venue:
  • ACM SIGGRAPH 2004 Course Notes
  • Year:
  • 2004

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Abstract

This course serves as a practical guide to ray tracing and photon mapping. The notes are mostly aimed at readers familiar with ray tracing, who would like to add an efficient implementation of photon mapping to an existing ray tracer. The course itself also includes a description of the ray tracing algorithm.There are many reasons to augment a ray tracer with photon maps. Photon maps makes it possible to efficiently compute global illumination including caustics, diffuse color bleeding, and participating media. Photon maps can be used in scenes containing many complex objects of general type (i.e. the method is not restricted to tessellated models). The method is capable of handling advanced material descriptions based on a mixture of specular, diffuse, and non-diffuse components. Furthermore, the method is easy to implement and experiment with.This course is structured as a half day course. We will therefore assume that the participants have knowledge of global illumination algorithms (in particular ray tracing), material models, and radiometric terms such as radiance and flux. We will discuss in detail photon tracing, the photon map data structure, the photon map radiance estimate, and rendering techniques based on photon maps. We will emphasize the techniques for efficient computation throughout the presentation. Finally, we will present several examples of scenes rendered with photon maps and explain the important aspects that we considered when rendering each scene.