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Revision 1.10 by greg, Wed Apr 6 22:00:46 2011 UTC

# Line 1 | Line 1
1   <html>
2   <head>
3   <title>
4 < The RADIANCE 3.8 Synthetic Imaging System
4 > The RADIANCE 4.1 Synthetic Imaging System
5   </title>
6   </head>
7   <body>
# Line 9 | Line 9 | The RADIANCE 3.8 Synthetic Imaging System
9   <p>
10  
11   <h1>
12 < The RADIANCE 3.8 Synthetic Imaging System
12 > The RADIANCE 4.1 Synthetic Imaging System
13   </h1>
14  
15   <p>
# Line 1053 | Line 1053 | unless the line integrals consider enclosed geometry.
1053   <p>
1054  
1055   <dt>
1056 +        <a NAME="BSDF">
1057 +        <b>BSDF</b>
1058 +        </a>
1059 +
1060 + <dd>
1061 +        The BSDF material type loads an XML (eXtensible Markup Language)
1062 +        file describing a bidirectional scattering distribution function.
1063 +        Real arguments to this material may define additional
1064 +        diffuse components that augment the BSDF data.
1065 +        String arguments are used to define thickness for proxied
1066 +        surfaces and the "up" orientation for the material.
1067 +
1068 + <pre>
1069 +        mod BSDF id
1070 +        6+ thick BSDFfile ux uy uz funcfile transform
1071 +        0
1072 +        0|3|6|9
1073 +                rfdif gfdif bfdif
1074 +                rbdif gbdif bbdif
1075 +                rtdif gtdif btdif
1076 + </pre>
1077 +
1078 + <p>
1079 +        The first string argument is a "thickness" parameter that may be used
1080 +        to hide detail geometry being proxied by an aggregate BSDF material.
1081 +        If a view or shadow ray hits a BSDF proxy with non-zero thickness,
1082 +        it will pass directly through as if the surface were not there.
1083 +        Similar to the illum type, this permits direct viewing and
1084 +        shadow testing of complex geometry.
1085 +        The BSDF is used when a scattered (indirect) ray hits the surface,
1086 +        and any transmitted sample rays will be offset by the thickness amount
1087 +        to avoid the hidden geometry and gather samples from the other side.
1088 +        In this manner, BSDF surfaces can improve the results for indirect
1089 +        scattering from complex systems without sacrificing appearance or
1090 +        shadow accuracy.
1091 +        If the BSDF has transmission and back-side reflection data,
1092 +        a parallel BSDF surface may be
1093 +        placed slightly less than the given thickness away from the front surface
1094 +        to enclose the complex geometry on both sides.
1095 + <p>
1096 +        The second string argument is the name of the BSDF file, which is
1097 +        found in the usual auxiliary locations.
1098 +        The following three string parameters name variables for an "up" vector,
1099 +        which together with the surface normal, define the
1100 +        local coordinate system that orients the BSDF.
1101 +        These variables, along with the thickness, are defined in a function
1102 +        file given as the next string argument.
1103 +        An optional transform is used to scale the thickness and reorient the up vector.
1104 + <p>
1105 +        If no real arguments are given, the BSDF is used by itself to determine
1106 +        reflection and transmission.
1107 +        If there are at least 3 real arguments, the first triplet is an
1108 +        additional diffuse reflectance for the front side.
1109 +        At least 6 real arguments adds diffuse reflectance to the rear side of the surface.
1110 +        If there are 9 real arguments, the final triplet will be taken as an additional
1111 +        diffuse transmittance.
1112 +        All diffuse components as well as the non-diffuse transmission are
1113 +        modified by patterns applied to this material.
1114 +        The non-diffuse reflection from either side are unaffected.
1115 +        Textures perturb the effective surface normal in the usual way.
1116 + <p>
1117 +        The surface normal of this type is not altered to face the incoming ray,
1118 +        so the front and back BSDF reflections may differ.
1119 +        (Transmission is identical front-to-back by physical law.)\0
1120 +        If back visibility is turned off during rendering and there is no
1121 +        transmission or back-side reflection, only then the surface will be
1122 +        invisible from behind.
1123 +        Unlike other data-driven material types, the BSDF type is fully
1124 +        supported and all parts of the distribution are properly sampled.
1125 + <p>
1126 +
1127 + <dt>
1128          <a NAME="Antimatter">
1129          <b>Antimatter</b>
1130          </a>
# Line 1365 | Line 1437 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1437          which serves as a form of opacity control when used with a material.)
1438          Vname is the coefficient defined in funcfile that determines  the  influence  of  foreground.  
1439          The background coefficient is always (1-vname).  
1368 –        Since the references are not resolved until run-time,  the  last  definitions  of  the modifier id's will be used.  
1369 –        This can result in modifier loops, which are detected by the renderer.
1440  
1441   <p>
1442  
# Line 1528 | Line 1598 | If no file is needed by a given primitive because all
1598   the  required  variables  are global,  
1599   a  period  (`.')  can be given in place of the file name.  
1600   It is also possible to give an expression instead
1601 < of a  straight  variable  name  in  a scene file,
1602 < although such expressions should be kept
1533 < simple if possible.
1534 < Also, functions (requiring parameters) must be given
1601 > of a  straight  variable  name  in  a scene file.
1602 > Functions (requiring parameters) must be given
1603   as names and not as expressions.
1604  
1605   <p>
# Line 1749 | Line 1817 | or converted a standard image format using one of the
1817   <pre>
1818   The Radiance Software License, Version 1.0
1819  
1820 < Copyright (c) 1990 - 2006 The Regents of the University of California,
1820 > Copyright (c) 1990 - 2010 The Regents of the University of California,
1821   through Lawrence Berkeley National Laboratory.   All rights reserved.
1822  
1823   Redistribution and use in source and binary forms, with or without
# Line 1823 | Line 1891 | Ecole  Polytechnique  Federale de Lausanne (EPFL Unive
1891   <p>
1892   <ul>
1893      <li>Cater, Kirsten, Alan Chalmers, Greg Ward,
1894 <        &quot;<a href="papers/egsr2003.pdf">Detail to Attention:
1894 >        &quot;<a href="http://www.anyhere.com/gward/papers/egsr2003.pdf">Detail to Attention:
1895          Exploiting Visual Tasks for Selective Rendering</a>,&quot;
1896          <em>Eurographics Symposium
1897          on Rendering 2003</em>, June 2003.
1898      <li>Ward, Greg, Elena Eydelberg-Vileshin,
1899 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/egwr02/index.html">Picture Perfect RGB
1899 >        ``<a HREF="http://www.anyhere.com/gward/papers/egwr02/index.html">Picture Perfect RGB
1900          Rendering Using Spectral Prefiltering and Sharp Color Primaries</a>,''
1901          Thirteenth Eurographics Workshop on Rendering (2002),
1902          P. Debevec and S. Gibson (Editors), June 2002.
1903      <li>Ward, Gregory,
1904 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/cic01.pdf">High Dynamic Range Imaging</a>,''
1904 >        ``<a HREF="http://www.anyhere.com/gward/papers/cic01.pdf">High Dynamic Range Imaging</a>,''
1905          Proceedings of the Ninth Color Imaging Conference, November 2001.
1906      <li>Ward, Gregory and Maryann Simmons,
1907 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/tog99.pdf">
1907 >        ``<a HREF="http://www.anyhere.com/gward/papers/tog99.pdf">
1908          The Holodeck Ray Cache: An Interactive Rendering System for Global Illumination in Nondiffuse
1909          Environments</a>,'' ACM Transactions on Graphics, 18(4):361-98, October 1999.
1910 <    <li>Larson, G.W., ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/ewp98.pdf">The Holodeck: A Parallel
1910 >    <li>Larson, G.W., ``<a HREF="http://www.anyhere.com/gward/papers/ewp98.pdf">The Holodeck: A Parallel
1911          Ray-caching Rendering System</a>,'' Proceedings of the Second
1912          Eurographics Workshop on Parallel Graphics and Visualisation,
1913          September 1998.
# Line 1925 | Line 1993 | SURFACES       MATERIALS       TEXTURES        PATTERNS        MIXTURES</h4>
1993                  <a HREF="#Plasdata">Plasdata</a>
1994                  <a HREF="#Metdata">Metdata</a>
1995                  <a HREF="#Transdata">Transdata</a>
1996 +                <a HREF="#BSDF">BSDF</a>
1997                  <a HREF="#Antimatter">Antimatter</a>
1998                                  
1999   </pre>

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