Bidirectional scattering distribution function: Difference between revisions

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The definition of the '''BSDF''' ('''Bidirectional scattering distribution function''') is not well standardized. The term was probably introduced in 1980 by Bartell, Dereniak, and Wolfe<ref name=bartell1980>{{Ref|endnote_bartell1980}}. Most often it is used to name the general mathematical function which describes the way in which the light is scattered by a surface. However in practice this phenomenon is usually split into the reflected and transmitted components, which are then treated separately as '''BRDF''' ('''[[Bidirectional reflectance distribution function]]''') and '''BTDF''' ('''Bidirectional transmittance distributioncite function''').web

|last1=Bartell

|first1=F. O.

|last2=Dereniak

|first2=E. L.

|last3=Wolfe

|first3=W. L.

|title=The theory and measurement of bidirectional reflectance distribution function (BRDF) and bidirectional transmittance distribution function (BTDF)

|url=http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1230783

|publisher=Proceedings of SPIE Vol. 257 Radiation Scattering in Optical Systems

|accessdate=14 July 2014

|pages=154-160

|doi=10.1117/12.959611

|year=1980}}

</ref>. Most often it is used to name the general mathematical function which describes the way in which the light is scattered by a surface. However in practice this phenomenon is usually split into the reflected and transmitted components, which are then treated separately as '''BRDF''' ('''[[Bidirectional reflectance distribution function]]''') and '''BTDF''' ('''Bidirectional transmittance distribution function''').

[[Image:BSDF05 800.png|thumb|right|280px|BSDF: BRDF + BTDF]]

Line 41 ⟶ 55:

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

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

*'''BSSRDF''' ('''Bidirectional scattering-surface reflectance distribution function''' or '''B surface scattering RDF''')<ref name=nicodemus1977>{{Ref|endnote_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 acite surface.web

|last1=Nicodemus

*'''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'').

|first1=F. E.

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

|last2=Richmond

|first2=J. C.

|last3=Hsia

|first3=J. J.

|last4=Ginsberg

|first4=I. W.

|last5=Limperis

|first5=T.

|title=Geometrical Considerations and Nomenclature for Reflectance

|url=http://graphics.stanford.edu/courses/cs448-05-winter/papers/nicodemus-brdf-nist.pdf

|publisher=Technical Report NBS MN-160, National Bureau of Standards

|accessdate=14 July 2014

|year=1977}}

</ref><ref name=jensen2001>{{cite web

|last1=Jensen

|first1=H. W.

|last2=Marschner

|first2=S. R.

|last3=Levoy

|first3=M.

|last4=Hanrahan

|first4=P.

|title=A Practical Model for Subsurface Light Transport

|url=http://dl.acm.org/citation.cfm?id=383319

|website=http://graphics.ucsd.edu/~henrik/papers/bssrdf/

|publisher=Proceedings of ACM SIGGRAPH 2001

|accessdate=14 July 2014

|pages=511-518

|doi=10.1145/383259.383319

|year=2001}}</ref> 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]]''')<ref name="nicodemus1977"/> 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''')<ref name="bartell1980"/> is similar to BRDF but for the opposite side of the surface. (''see the top image'').

==See also==

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==References==

{{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_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.

==External links==