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Bridge Sampling for Connections via Multiple Scattering Events

Schüßler, Vincent ORCID iD icon 1; Hanika, Johannes 1; Dachsbacher, Carsten 1
1 Institut für Visualisierung und Datenanalyse (IVD), Karlsruher Institut für Technologie (KIT)

Abstract:

Explicit sampling of and connecting to light sources is often essential for reducing variance in Monte Carlo rendering. In dense, forward-scattering participating media, its benefit declines, as significant transport happens over longer multiple-scattering paths around the straight connection to the light. Sampling these paths is challenging, as their contribution is shaped by the product of reciprocal squared distance terms and the phase functions. Previous work demonstrates that sampling several of these terms jointly is crucial. However, these methods are tied to low-order scattering or struggle with highly-peaked phase functions.
We present a method for sampling a bridge: a subpath of arbitrary vertex count connecting two vertices. Its probability density is proportional to all phase functions at inner vertices and reciprocal squared distance terms. To achieve this, we importance sample the phase functions first, and subsequently all distances at once. For the latter, we sample an independent, preliminary distance for each edge of the bridge, and afterwards scale the bridge such that it matches the connection distance. The scale factor can be marginalized out analytically to obtain the probability density of the bridge. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000173004
Veröffentlicht am 09.08.2024
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Visualisierung und Datenanalyse (IVD)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 07.2024
Sprache Englisch
Identifikator ISSN: 0167-7055, 1467-8659
KITopen-ID: 1000173004
Erschienen in Computer Graphics Forum
Verlag John Wiley and Sons
Band 43
Heft 4
Seiten Art.-Nr.: e15160
Vorab online veröffentlicht am 24.07.2024
Schlagwörter CCS Concepts, Computing methodologies, Rendering, Ray tracing
Nachgewiesen in Dimensions
Scopus
Web of Science
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