MC Ray Tracing: Part II, Importance Sampling Sung-Eui Yoon ( ) - - PowerPoint PPT Presentation

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MC Ray Tracing: Part II, Importance Sampling Sung-Eui Yoon ( ) - - PowerPoint PPT Presentation

Sep 06, 2022 244 likes •687 views

CS580: MC Ray Tracing: Part II, Importance Sampling Sung-Eui Yoon ( ) Course URL: http://sglab.kaist.ac.kr/~sungeui/GCG Class Objectives: I mportance sampling for: Direct terms Lights I ndirect terms 2 Performance

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CS580:

MC Ray Tracing: Part II, Importance Sampling

Sung-Eui Yoon (윤성의)

Course URL: http://sglab.kaist.ac.kr/~sungeui/GCG

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Class Objectives:

  • I mportance sampling for:
  • Direct terms
  • Lights
  • I ndirect terms
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Performance and Error

  • Want better quality with smaller number of

samples

  • Fewer samples  better performance
  • Stratified sampling
  • Quasi Monte Carlo: well-distributed samples
  • Faster convergence
  • I mportance sampling: next-event estimation
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Importance Sampling

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Importance Sampling

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Comparison

  • With and without considering direct

illumination

  • 16 samples / pixel

From kavita’s slides

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Anti-aliasing

From kavita’s slides

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Do not take visibility into account!

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Research on Many Lights

  • Ward 91
  • Sort lights based on their maximum

contribution

  • Pick bright lights based on a threshold
  • Do not consider visibility
  • Many other papers
  • One of recent works:
  • LightCuts: A Scalable Approach to I llumination,

SI G. 05, Walter et al.

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y  z  x

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General GI Algorithm

  • Design path generators
  • Path generators determine efficiency of GI

algorithm

  • Black boxes
  • Evaluate BRDF, ray intersection, visibility

evaluations, etc

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Class Objectives were:

  • I mportance sampling for:
  • Direct terms
  • Lights
  • I ndirect terms