ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/doc/ray.html
(Generate patch)

Comparing ray/doc/ray.html (file contents):
Revision 1.3 by greg, Thu Jan 1 19:31:44 2004 UTC vs.
Revision 1.25 by greg, Mon Jun 25 20:49:10 2018 UTC

# Line 1 | Line 1
1   <html>
2 + <!-- RCSid $Id$ -->
3   <head>
4   <title>
5 < The RADIANCE 3.5 Synthetic Imaging System
5 > The RADIANCE 5.2 Synthetic Imaging System
6   </title>
7   </head>
8   <body>
9  
9 – Copyright � 2003 Regents, University of California
10 –
10   <p>
11  
12   <h1>
13 < The RADIANCE 3.5 Synthetic Imaging System
13 > The RADIANCE 5.2 Synthetic Imaging System
14   </h1>
15  
16   <p>
17  
18 < Building Technologies Department<br>
18 > Building Technologies Program<br>
19   Lawrence Berkeley National Laboratory<br>
20   1 Cyclotron Rd., 90-3111<br>
21   Berkeley, CA  94720<br>
# Line 566 | Line 565 | A material defines the way light interacts with a  sur
565          </a>
566  
567   <dd>
568 <        Mirror is used for planar surfaces that produce  secondary source reflections.  
568 >        Mirror is used for planar surfaces that produce  virtual source reflections.  
569          This material should be used sparingly, as it may cause the light source calculation to  blow up  if  it is applied to many small surfaces.  
570          This material is only supported for flat surfaces  such  as  <a HREF="#Polygon">polygons</a>  and <a HREF="#Ring">rings</a>.  
571          The arguments are simply the RGB reflectance values, which should be between 0 and 1.  
# Line 589 | Line 588 | This is only appropriate if the surface hides other (m
588          </a>
589  
590   <dd>
591 <        The prism1 material is for  general  light  redirection from prismatic glazings, generating secondary light sources.
591 >        The prism1 material is for  general  light  redirection from prismatic glazings, generating virtual light sources.
592          It can only be used  to  modify  a  planar  surface  
593          (i.e.,  a <a HREF="#Polygon">polygon</a>  or <a HREF="#Ring">disk</a>)
594          and should not result in either light concentration or scattering.  
595          The new direction of the ray  can be  on either side of the material,
596 <        and the definitions must have the correct bidirectional properties to  work  properly with  secondary light sources.  
596 >        and the definitions must have the correct bidirectional properties to  work  properly with virtual light sources.  
597          The arguments give the coefficient for the redirected light and its direction.
598  
599   <pre>
# Line 661 | Line 660 | a perfectly scattering medium (no absorption).
660   The scattering eccentricity parameter will likewise override the global
661   setting if it is present.
662   Scattering eccentricity indicates how much scattered light favors the
663 < forward direction, as fit by the Heyney-Greenstein function:
663 > forward direction, as fit by the Henyey-Greenstein function:
664  
665   <pre>
666          P(theta) = (1 - g*g) / (1 + g*g - 2*g*cos(theta))^1.5
# Line 799 | Line 798 | unless the line integrals consider enclosed geometry.
798  
799   <dd>
800          Trans2 is the anisotropic version of <a HREF="#Trans">trans</a>.  
801 <        The string arguments  are  the same as for plastic2, and the real arguments are the same as  for  trans  but  with  an  additional roughness value.
801 >        The string arguments  are  the same as for <a HREF="#Plastic2">plastic2</a>,
802 >        and the real arguments are the same as  for  trans  but  with  an  additional roughness value.
803  
804   <pre>
805          mod trans2 id
# Line 811 | Line 811 | unless the line integrals consider enclosed geometry.
811   <p>
812  
813   <dt>
814 +        <a NAME="Ashik2">
815 +        <b>Ashik2</b>
816 +        </a>
817 +
818 + <dd>
819 +        Ashik2 is the anisotropic reflectance model by Ashikhmin & Shirley.
820 +        The string arguments are the same as for <a HREF="#Plastic2">plastic2</a>, but the real
821 +        arguments have additional flexibility to specify the specular color.
822 +        Also, rather than roughness, specular power is used, which has no
823 +        physical meaning other than larger numbers are equivalent to a smoother
824 +        surface.
825 + <pre>
826 +        mod ashik2 id
827 +        4+ ux uy uz funcfile transform
828 +        0
829 +        8 dred dgrn dblu sred sgrn sblu u-power v-power
830 + </pre>
831 +
832 + <p>
833 +
834 + <dt>
835          <a NAME="Dielectric">
836          <b>Dielectric</b>
837          </a>
# Line 1055 | Line 1076 | unless the line integrals consider enclosed geometry.
1076   <p>
1077  
1078   <dt>
1079 +        <a NAME="BSDF">
1080 +        <b>BSDF</b>
1081 +        </a>
1082 +
1083 + <dd>
1084 +        The BSDF material type loads an XML (eXtensible Markup Language)
1085 +        file describing a bidirectional scattering distribution function.
1086 +        Real arguments to this material may define additional
1087 +        diffuse components that augment the BSDF data.
1088 +        String arguments are used to define thickness for proxied
1089 +        surfaces and the &quot;up&quot; orientation for the material.
1090 +
1091 + <pre>
1092 +        mod BSDF id
1093 +        6+ thick BSDFfile ux uy uz funcfile transform
1094 +        0
1095 +        0|3|6|9
1096 +                rfdif gfdif bfdif
1097 +                rbdif gbdif bbdif
1098 +                rtdif gtdif btdif
1099 + </pre>
1100 +
1101 + <p>
1102 +        The first string argument is a &quot;thickness&quot; parameter that may be used
1103 +        to hide detail geometry being proxied by an aggregate BSDF material.
1104 +        If a view or shadow ray hits a BSDF proxy with non-zero thickness,
1105 +        it will pass directly through as if the surface were not there.
1106 +        Similar to the illum type, this permits direct viewing and
1107 +        shadow testing of complex geometry.
1108 +        The BSDF is used when a scattered (indirect) ray hits the surface,
1109 +        and any transmitted sample rays will be offset by the thickness amount
1110 +        to avoid the hidden geometry and gather samples from the other side.
1111 +        In this manner, BSDF surfaces can improve the results for indirect
1112 +        scattering from complex systems without sacrificing appearance or
1113 +        shadow accuracy.
1114 +        If the BSDF has transmission and back-side reflection data,
1115 +        a parallel BSDF surface may be
1116 +        placed slightly less than the given thickness away from the front surface
1117 +        to enclose the complex geometry on both sides.
1118 +        The sign of the thickness is important, as it indicates
1119 +        whether the proxied geometry is behind the BSDF
1120 +        surface (when thickness is positive) or in front (when
1121 +        thickness is negative).
1122 + <p>
1123 +        The second string argument is the name of the BSDF file,
1124 +        which is found in the usual auxiliary locations.  The
1125 +        following three string parameters name variables for an
1126 +        &quot;up&quot; vector, which together with the surface
1127 +        normal, define the local coordinate system that orients the
1128 +        BSDF.  These variables, along with the thickness, are defined
1129 +        in a function file given as the next string argument.  An
1130 +        optional transform is used to scale the thickness and
1131 +        reorient the up vector.
1132 + <p>
1133 +        If no real arguments are given, the BSDF is used by itself
1134 +        to determine reflection and transmission.  If there are at
1135 +        least 3 real arguments, the first triplet is an additional
1136 +        diffuse reflectance for the front side.  At least 6 real
1137 +        arguments adds diffuse reflectance to the rear side of the
1138 +        surface.  If there are 9 real arguments, the final triplet
1139 +        will be taken as an additional diffuse transmittance.  All
1140 +        diffuse components as well as the non-diffuse transmission
1141 +        are modified by patterns applied to this material.  The
1142 +        non-diffuse reflection from either side are unaffected.
1143 +        Textures perturb the effective surface normal in the usual
1144 +        way.
1145 + <p>
1146 +        The surface normal of this type is not altered to face the
1147 +        incoming ray, so the front and back BSDF reflections may
1148 +        differ.  (Transmission is identical front-to-back by physical
1149 +        law.) If back visibility is turned off during rendering and
1150 +        there is no transmission or back-side reflection, only then
1151 +        the surface will be invisible from behind.  Unlike other
1152 +        data-driven material types, the BSDF type is fully supported
1153 +        and all parts of the distribution are properly sampled.
1154 + <p>
1155 +
1156 + <dt>
1157 +        <a NAME="sBSDF">
1158 +        <b>sBSDF</b>
1159 +        </a>
1160 +
1161 + <dd>
1162 +        The sBSDF material is identical to the BSDF type with two
1163 +        important differences.  First, proxy geometry is not
1164 +        supported, so there is no thickness parameter.  Second, an
1165 +        sBSDF is assumed to have some specular through component,
1166 +        which is treated specially during the direct calculation
1167 +        and when viewing the material.  Based on the BSDF data, the
1168 +        coefficient of specular transmission is determined and used
1169 +        for modifying unscattered shadow and view rays.
1170 +
1171 + <pre>
1172 +        mod sBSDF id
1173 +        5+ BSDFfile ux uy uz funcfile transform
1174 +        0
1175 +        0|3|6|9
1176 +             rfdif gfdif bfdif
1177 +             rbdif gbdif bbdif
1178 +             rtdif gtdif btdif
1179 + </pre>
1180 +
1181 + <p>
1182 +        If a material has no specular transmitted component, it is
1183 +        much better to use the BSDF type with a zero thickness
1184 +        than to use sBSDF.
1185 + <p>
1186 +
1187 + <dt>
1188          <a NAME="Antimatter">
1189          <b>Antimatter</b>
1190          </a>
# Line 1338 | Line 1468 | or:
1468   </h4>
1469  
1470   A mixture is a blend of one or more materials or textures and patterns.
1471 + Blended materials should not be light source types or virtual source types.
1472   The basic types are given below.
1473  
1474   <p>
# Line 1367 | Line 1498 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1498          which serves as a form of opacity control when used with a material.)
1499          Vname is the coefficient defined in funcfile that determines  the  influence  of  foreground.  
1500          The background coefficient is always (1-vname).  
1370 –        Since the references are not resolved until run-time,  the  last  definitions  of  the modifier id's will be used.  
1371 –        This can result in modifier loops, which are detected by the renderer.
1501  
1502   <p>
1503  
# Line 1412 | Line 1541 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1541          arguments, the red, green and blue values
1542          corresponding to the pixel at (u,v).
1543  
1415 – </dl>
1544   <p>
1545  
1546   <dt>
# Line 1530 | Line 1658 | If no file is needed by a given primitive because all
1658   the  required  variables  are global,  
1659   a  period  (`.')  can be given in place of the file name.  
1660   It is also possible to give an expression instead
1661 < of a  straight  variable  name  in  a scene file,
1662 < although such expressions should be kept
1535 < simple if possible.
1536 < Also, functions (requiring parameters) must be given
1661 > of a  straight  variable  name  in  a scene file.
1662 > Functions (requiring parameters) must be given
1663   as names and not as expressions.
1664  
1665   <p>
# Line 1716 | Line 1842 | Pictures may be displayed directly under X11 using the
1842   or converted a standard image format using one of the following
1843   <b>translators</b>:
1844          <ul>
1845 <        <li> <b>Ra_avs</b>
1846 <                converts to and from AVS image format.
1721 <        <li> <a HREF="../man_html/ra_pict.1.html"><b>Ra_pict</b></a>
1722 <                converts to Macintosh 32-bit PICT2 format.
1845 >        <li> <a HREF="../man_html/ra_bmp.1.html"><b>Ra_bmp</b>
1846 >                converts to and from BMP image format.
1847          <li> <a HREF="../man_html/ra_ppm.1.html"><b>Ra_ppm</b></a>
1848                  converts to and from Poskanzer Portable Pixmap formats.
1725 –        <li> <a HREF="../man_html/ra_pr.1.html"><b>Ra_pr</b></a>
1726 –                converts to and from Sun 8-bit rasterfile format.
1727 –        <li> <a HREF="../man_html/ra_pr24.1.html"><b>Ra_pr24</b></a>
1728 –                converts to and from Sun 24-bit rasterfile format.
1849          <li> <a HREF="../man_html/ra_ps.1.html"><b>Ra_ps</b></a>
1850                  converts to PostScript color and greyscale formats.
1851          <li> <a HREF="../man_html/ra_rgbe.1.html"><b>Ra_rgbe</b></a>
# Line 1751 | Line 1871 | or converted a standard image format using one of the
1871   <pre>
1872   The Radiance Software License, Version 1.0
1873  
1874 < Copyright (c) 1990 - 2002 The Regents of the University of California,
1874 > Copyright (c) 1990 - 2014 The Regents of the University of California,
1875   through Lawrence Berkeley National Laboratory.   All rights reserved.
1876  
1877   Redistribution and use in source and binary forms, with or without
# Line 1785 | Line 1905 | are met:
1905        nor may &quot;Radiance&quot; appear in their name, without prior written
1906        permission of Lawrence Berkeley National Laboratory.
1907  
1908 < THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
1908 > THIS SOFTWARE IS PROVIDED ``AS IS&quot; AND ANY EXPRESSED OR IMPLIED
1909   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1910   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1911   DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
# Line 1824 | Line 1944 | Ecole  Polytechnique  Federale de Lausanne (EPFL Unive
1944   </h2>
1945   <p>
1946   <ul>
1947 +    <li>McNeil, A., C.J. Jonsson, D. Appelfeld, G. Ward, E.S. Lee,
1948 +        &quot;<a href="http://gaia.lbl.gov/btech/papers/4414.pdf">
1949 +        A validation of a ray-tracing tool used to generate
1950 +        bi-directional scattering distribution functions for
1951 +        complex fenestration systems</a>,&quot;
1952 +        <em>Solar Energy</em>, 98, 404-14,
1953 +        November 2013.
1954 +    <li>Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson,
1955 +        &quot;<a href="http://gaia.lbl.gov/btech/papers/4414.pdf">Simulating
1956 +        the Daylight Performance of Complex Fenestration Systems
1957 +        Using Bidirectional Scattering Distribution Functions within
1958 +        Radiance</a>,&quot;
1959 +        <em>Leukos</em>, 7(4)
1960 +        April 2011.
1961 +    <li>Cater, Kirsten, Alan Chalmers, Greg Ward,
1962 +        &quot;<a href="http://www.anyhere.com/gward/papers/egsr2003.pdf">Detail to Attention:
1963 +        Exploiting Visual Tasks for Selective Rendering</a>,&quot;
1964 +        <em>Eurographics Symposium
1965 +        on Rendering 2003</em>, June 2003.
1966      <li>Ward, Greg, Elena Eydelberg-Vileshin,
1967 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/egwr02/index.html">Picture Perfect RGB
1968 <        Rendering Using Spectral Prefiltering and Sharp Color Primaries</a>,''
1967 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/egwr02/index.html">Picture Perfect RGB
1968 >        Rendering Using Spectral Prefiltering and Sharp Color Primaries</a>,&quot;
1969          Thirteenth Eurographics Workshop on Rendering (2002),
1970          P. Debevec and S. Gibson (Editors), June 2002.
1971      <li>Ward, Gregory,
1972 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/cic01.pdf">High Dynamic Range Imaging</a>,''
1972 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/cic01.pdf">High Dynamic Range Imaging</a>,&quot;
1973          Proceedings of the Ninth Color Imaging Conference, November 2001.
1974      <li>Ward, Gregory and Maryann Simmons,
1975 <        ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/tog99.pdf">
1975 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/tog99.pdf">
1976          The Holodeck Ray Cache: An Interactive Rendering System for Global Illumination in Nondiffuse
1977 <        Environments</a>,'' ACM Transactions on Graphics, 18(4):361-98, October 1999.
1978 <    <li>Larson, G.W., ``<a HREF="http://viz.cs.berkeley.edu/~gwlarson/papers/ewp98.pdf">The Holodeck: A Parallel
1979 <        Ray-caching Rendering System</a>,'' Proceedings of the Second
1977 >        Environments</a>,&quot; ACM Transactions on Graphics, 18(4):361-98, October 1999.
1978 >    <li>Larson, G.W., &quot;<a HREF="http://www.anyhere.com/gward/papers/ewp98.pdf">The Holodeck: A Parallel
1979 >        Ray-caching Rendering System</a>,&quot; Proceedings of the Second
1980          Eurographics Workshop on Parallel Graphics and Visualisation,
1981          September 1998.
1982      <li>Larson, G.W. and R.A. Shakespeare,
# Line 1845 | Line 1984 | Ecole  Polytechnique  Federale de Lausanne (EPFL Unive
1984          the Art and Science of Lighting Visualization</em></a>,
1985          Morgan Kaufmann Publishers, 1998.
1986      <li>Larson, G.W., H. Rushmeier, C. Piatko,
1987 <        ``<a HREF="http://radsite.lbl.gov/radiance/papers/lbnl39882/tonemap.pdf">A Visibility
1987 >        &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/lbnl39882/tonemap.pdf">A Visibility
1988          Matching Tone Reproduction Operator for
1989 <        High Dynamic Range Scenes</a>,'' LBNL Technical Report 39882,
1989 >        High Dynamic Range Scenes</a>,&quot; LBNL Technical Report 39882,
1990          January 1997.
1991 <    <li>Ward, G., ``<a HREF="http://radsite.lbl.gov/radiance/papers/erw95.1/paper.html">Making
1992 <        Global Illumination User-Friendly</a>,'' Sixth
1991 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw95.1/paper.html">Making
1992 >        Global Illumination User-Friendly</a>,&quot; Sixth
1993          Eurographics Workshop on Rendering, Springer-Verlag,
1994          Dublin, Ireland, June 1995.</li>
1995      <li>Rushmeier, H., G. Ward, C. Piatko, P. Sanders, B. Rust,
1996 <        ``<a HREF="http://radsite.lbl.gov/mgf/compare.html">
1996 >        &quot;<a HREF="http://radsite.lbl.gov/mgf/compare.html">
1997          Comparing Real and Synthetic Images: Some Ideas about
1998 <        Metrics</a>,'' Sixth Eurographics Workshop on Rendering,
1998 >        Metrics</a>,&quot; Sixth Eurographics Workshop on Rendering,
1999          Springer-Verlag, Dublin, Ireland, June 1995.</li>
2000 <    <li>Ward, G., ``<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.1/paper.html">The RADIANCE
2001 <        Lighting Simulation and Rendering System</a>,'' <em>Computer
2000 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.1/paper.html">The RADIANCE
2001 >        Lighting Simulation and Rendering System</a>,&quot; <em>Computer
2002          Graphics</em>, July 1994.</li>
2003 <    <li>Rushmeier, H., G. Ward, ``<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.2/energy.html">Energy
2004 <        Preserving Non-Linear Filters</a>,'' <em>Computer
2003 >    <li>Rushmeier, H., G. Ward, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.2/energy.html">Energy
2004 >        Preserving Non-Linear Filters</a>,&quot; <em>Computer
2005          Graphics</em>, July 1994.</li>
2006 <    <li>Ward, G., ``A Contrast-Based Scalefactor for Luminance
2007 <        Display,'' <em>Graphics Gems IV</em>, Edited by Paul Heckbert,
2006 >    <li>Ward, G., &quot;A Contrast-Based Scalefactor for Luminance
2007 >        Display,&quot; <em>Graphics Gems IV</em>, Edited by Paul Heckbert,
2008          Academic Press 1994.</li>
2009 <    <li>Ward, G., ``<a HREF="http://radsite.lbl.gov/radiance/papers/sg92/paper.html">Measuring and
2010 <        Modeling Anisotropic Reflection</a>,'' <em>Computer
2009 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg92/paper.html">Measuring and
2010 >        Modeling Anisotropic Reflection</a>,&quot; <em>Computer
2011          Graphics</em>, Vol. 26, No. 2, July 1992. </li>
2012 <    <li>Ward, G., P. Heckbert, ``<a HREF="http://radsite.lbl.gov/radiance/papers/erw92/paper.html">Irradiance
2013 <        Gradients</a>,'' Third Annual Eurographics Workshop on
2012 >    <li>Ward, G., P. Heckbert, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw92/paper.html">Irradiance
2013 >        Gradients</a>,&quot; Third Annual Eurographics Workshop on
2014          Rendering, Springer-Verlag, May 1992. </li>
2015 <    <li>Ward, G., ``<a HREF="http://radsite.lbl.gov/radiance/papers/erw91/erw91.html">Adaptive Shadow
2016 <        Testing for Ray Tracing</a>'' Photorealistic Rendering in
2015 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw91/erw91.html">Adaptive Shadow
2016 >        Testing for Ray Tracing</a>&quot; Photorealistic Rendering in
2017          Computer Graphics, proceedings of 1991 Eurographics
2018          Rendering Workshop, edited by P. Brunet and F.W. Jansen,
2019          Springer-Verlag. </li>
2020 <    <li>Ward, G., ``Visualization,'' <em>Lighting Design and
2020 >    <li>Ward, G., &quot;Visualization,&quot; <em>Lighting Design and
2021          Application</em>, Vol. 20, No. 6, June 1990. </li>
2022 <    <li>Ward, G., F. Rubinstein, R. Clear, ``<a HREF="http://radsite.lbl.gov/radiance/papers/sg88/paper.html">A Ray Tracing Solution for
2023 <        Diffuse Interreflection</a>,'' <em>Computer Graphics</em>,
2022 >    <li>Ward, G., F. Rubinstein, R. Clear, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg88/paper.html">A Ray Tracing Solution for
2023 >        Diffuse Interreflection</a>,&quot; <em>Computer Graphics</em>,
2024          Vol. 22, No. 4, August 1988. </li>
2025 <    <li>Ward, G., F. Rubinstein, ``A New Technique for Computer
2026 <        Simulation of Illuminated Spaces,'' <em>Journal of the
2025 >    <li>Ward, G., F. Rubinstein, &quot;A New Technique for Computer
2026 >        Simulation of Illuminated Spaces,&quot; <em>Journal of the
2027          Illuminating Engineering Society</em>, Vol. 17, No. 1,
2028          Winter 1988. </li>
2029   </ul>
# Line 1922 | Line 2061 | SURFACES       MATERIALS       TEXTURES        PATTERNS        MIXTURES</h4>
2061                  <a HREF="#Plasdata">Plasdata</a>
2062                  <a HREF="#Metdata">Metdata</a>
2063                  <a HREF="#Transdata">Transdata</a>
2064 +                <a HREF="#BSDF">BSDF</a>
2065                  <a HREF="#Antimatter">Antimatter</a>
2066                                  
2067   </pre>

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines