Importance Sampling Microfacet-Based BSDFs using the Distribution of Visible Normals - Inria - Institut national de recherche en sciences et technologies du numérique Accéder directement au contenu
Article Dans Une Revue Computer Graphics Forum Année : 2014

Importance Sampling Microfacet-Based BSDFs using the Distribution of Visible Normals

Résumé

We present a new approach to microfacet-based BSDF importance sampling. Previously proposed sampling schemes for popular analytic BSDFs typically begin by choosing a microfacet normal at random in a way that is independent of direction of incident light. To sample the full BSDF using these normals requires arbitrarily large sample weights leading to possible fireflies. Additionally, at grazing angles nearly half of the sampled normals face away from the incident ray and must be rejected, making the sampling scheme inefficient. Instead, we show how to use the distribution of visible normals directly to generate samples, where normals are weighted by their projection factor toward the incident direction. In this way, no backfacing normals are sampled and the sample weights contain only the shadowing factor of outgoing rays (and additionally a Fresnel term for conductors). Arbitrarily large sample weights are avoided and variance is reduced. Since the BSDF depends on the microsurface model, we describe our sampling algorithm for two models: the V-cavity and the Smith models. We demonstrate results for both isotropic and anisotropic rough conductors and dielectrics with Beckmann and GGX distributions.
Fichier principal
Vignette du fichier
article.pdf (951.37 Ko) Télécharger le fichier
Vignette du fichier
heitzegsr2014.jpg (89.25 Ko) Télécharger le fichier
slides.pdf (6.32 Mo) Télécharger le fichier
supplemental1.pdf (1019.74 Ko) Télécharger le fichier
supplemental2.pdf (5.45 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Format : Figure, Image
Format : Autre
Format : Autre
Format : Autre
Loading...

Dates et versions

hal-00996995 , version 1 (27-05-2014)
hal-00996995 , version 2 (16-06-2014)

Identifiants

Citer

Eric Heitz, Eugene d'Eon. Importance Sampling Microfacet-Based BSDFs using the Distribution of Visible Normals. Computer Graphics Forum, 2014, 33 (4), pp.103-112. ⟨10.1111/cgf.12417⟩. ⟨hal-00996995v2⟩
9785 Consultations
18832 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More