Bidirectional scattering distribution function: Difference between revisions

Revision as of 10:03, 14 July 2014

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[[Image:BSSDF01 400.svg|thumb|right|250px|BRDF vs. BSSRDF]]

*'''BSDF''' ('''Bidirectional scattering distribution function''') is the most general function.

*'''BSSRDF''' ('''Bidirectional scattering-surface scattering reflectance distribution function''' or '''B scattering surface scattering RDF'''){{Ref|nicodemus_1977endnote_nicodemus1977}}{{Ref|endnote_jensen2001}}describes the relation between outgoing radiance and the incident flux, including the phenomena like [[subsurface scattering]] (SSS). The BSSRDF describes how light is transported between any two rays that hit a surface.

*'''BRDF''' ('''[[Bidirectional reflectance distribution function]]''') is a simplified BSSRDF, assuming that light enters and leaves at the same point (''see the image on the right'').

* '''BTDF''' ('''Bidirectional transmittance distribution function''') is similar to BRDF but for the opposite side of the surface. (''see the top image'').

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{{Reflist|2}}

# {{note |endnote_bartell1980}}F. O. Bartell, E. L. Dereniak, and W. L. Wolfe (1980), ''[http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1230783 "The theory and measurement of bidirectional reflectance distribution function (BRDF) and bidirectional transmittance distribution function (BTDF)"]''. Proceedings of SPIE Vol. 257 Radiation Scattering in Optical Systems, pp. 154-160.

#{{note |endnote_nicodemus1977}} F. E. Nicodemus, J. C. Richmond, J. J. Hsia, I. W. Ginsberg, and T. Limperis (1977), ''[http://graphics.stanford.edu/courses/cs448-05-winter/papers/nicodemus-brdf-nist.pdf "Geometrical Considerations and Nomenclature for Reflectance"]'' Technical Report NBS MN-160, National Bureau of Standards.

#{{note |endnote_rauw}} Randall Rauwendaal''[http://graphics.cs.ucdavis.edu/~bcbudge/ecs298_2004/General_BSDFs_BSSDFs.ppt "Rendering General BSDFs and BSSDFs"]''

#{{note |endnote_jensen2001}} H. W. Jensen, S. R. Marschner, M. Levoy, and P. Hanrahan (2001), ''[http://dl.acm.org/citation.cfm?id=383319 "A Practical Model for Subsurface Light Transport"]'' Proceedings of ACM SIGGRAPH 2001, pp. 511-518.

#{{note |nicodemus_1977}} The original definition in Nicodemus et al. 1977 has ''scattering surface'', but somewhere along the way, the word ordering was reversed.

==External links==