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# Line 1 | Line 1
1   <html>
2 + <!-- RCSid $Id$ -->
3   <head>
4   <title>
5 < The RADIANCE 3.5 Synthetic Imaging System
5 > The RADIANCE 6.0 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 6.0 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 76 | Line 75 | in  graphic  arts,  lighting  design,
75   computer-aided engineering and architecture.
76  
77   <p>
78 < <img SRC="diagram1.gif">
78 > <img SRC="diagram1.png">
79   <p>
81 – Figure 1
82 – <p>
80   The diagram in Figure 1 shows the flow between programs (boxes)  and  data  
81   (ovals).  
82   The central program is <i>rpict</i>, which produces a picture from a scene
83   description.
84 < <i>Rview</i> is a  variation  of  rpict  that  computes  and displays images
84 > <i>Rvu</i> is a  variation  of  rpict  that  computes  and displays images
85   interactively, and rtrace computes single ray values.
86   Other programs (not shown) connect many of these elements together,
87   such as the executive programs
# Line 149 | Line 146 | It is stored as ASCII  text,  with  the  following bas
146           ...
147   </pre>
148  
149 + <p>
150 +
151   A comment line begins with a pound sign, `#'.
152  
153   <p>
# Line 395 | Line 394 | The basic types are given below.
394          0
395   </pre>
396  
397 + <p>
398          If the modifier is &quot;void&quot;, then surfaces will
399          use the modifiers  given  in  the  original  description.  
400          Otherwise, the modifier specified is used in their  place.  
# Line 439 | Line 439 | The basic types are given below.
439          0
440   </pre>
441  
442 + <p>
443 +
444          If the modifier is &quot;void&quot;, then surfaces will
445          use the modifiers  given  in  the  original  mesh description.  
446          Otherwise, the modifier specified is used in their  place.  
# Line 533 | Line 535 | A material defines the way light interacts with a  sur
535          4 red green blue maxrad
536   </pre>
537  
538 + <p>
539          If maxrad is zero, then the surface will never be tested for shadow,  although  it  may participate in an interreflection calculation.  
540          If maxrad is negative, then the  surface  will never  contribute  to scene illumination.  
541          Glow sources will never illuminate objects on the other side of an illum  surface.  
# Line 566 | Line 569 | A material defines the way light interacts with a  sur
569          </a>
570  
571   <dd>
572 <        Mirror is used for planar surfaces that produce  secondary source reflections.  
572 >        Mirror is used for planar surfaces that produce  virtual source reflections.  
573          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.  
574          This material is only supported for flat surfaces  such  as  <a HREF="#Polygon">polygons</a>  and <a HREF="#Ring">rings</a>.  
575          The arguments are simply the RGB reflectance values, which should be between 0 and 1.  
# Line 581 | Line 584 | This is only appropriate if the surface hides other (m
584          3 red green blue
585   </pre>
586  
587 +        While alternate materials that are reflective will appear as normal,
588 +        indirect rays will use the mirror's reflectance rather than the
589 +        alternate type.
590 +        Transmitting materials are an exception, where both transmission and
591 +        reflection will use the alternate type for all rays not specifically
592 +        targeting virtual light sources.
593 +        In this case, it is important that any reflections be purely specular
594 +        (mirror-like) and equal to the mirror's reflectivity
595 +        to maintain a valid result.
596 +        A pure diffuse reflection may be added if desired.
597 +
598   <p>
599  
600 +        The mirror material type reflects light sources only from the front side
601 +        of a surface, regardless of any alternate material.
602 +        If virtual source generation is desired on both sides, two coincident
603 +        surfaces with opposite normal orientations may be employed to achieve
604 +        this effect.
605 +        The reflectance and alternate material type may be
606 +        different for the overlapped surfaces,
607 +        and the two sides will behave accordingly.
608 +
609 + <p>
610 +
611   <dt>
612          <a NAME="Prism1">
613          <b>Prism1</b>
614          </a>
615  
616   <dd>
617 <        The prism1 material is for  general  light  redirection from prismatic glazings, generating secondary light sources.
617 >        The prism1 material is for  general  light  redirection from prismatic glazings, generating virtual light sources.
618          It can only be used  to  modify  a  planar  surface  
619          (i.e.,  a <a HREF="#Polygon">polygon</a>  or <a HREF="#Ring">disk</a>)
620          and should not result in either light concentration or scattering.  
621          The new direction of the ray  can be  on either side of the material,
622 <        and the definitions must have the correct bidirectional properties to  work  properly with  secondary light sources.  
622 >        and the definitions must have the correct bidirectional properties to  work  properly with virtual light sources.  
623          The arguments give the coefficient for the redirected light and its direction.
624  
625   <pre>
# Line 604 | Line 629 | This is only appropriate if the surface hides other (m
629          n A1 A2 .. An
630   </pre>
631  
632 + <p>
633 +
634          The new direction variables dx, dy and dz need not produce a normalized  vector.  
635          For convenience, the variables DxA, DyA and DzA are defined as the normalized direction to the  target  light  source.  
636          See <a HREF="#Function">section 2.2.1</a> on function files for further information.
# Line 647 | Line 674 | This is only appropriate if the surface hides other (m
674          3  source1  mirror1&gt;source10  mirror2&gt;mirror1&gt;source3
675   </pre>
676  
677 + <p>
678   Normally, only one source is given per mist material, and there is an
679   upper limit of 32 to the total number of active scattering sources.
680   The extinction coefficient, if given, is added the the global
# Line 661 | Line 689 | a perfectly scattering medium (no absorption).
689   The scattering eccentricity parameter will likewise override the global
690   setting if it is present.
691   Scattering eccentricity indicates how much scattered light favors the
692 < forward direction, as fit by the Heyney-Greenstein function:
692 > forward direction, as fit by the Henyey-Greenstein function:
693  
694   <pre>
695          P(theta) = (1 - g*g) / (1 + g*g - 2*g*cos(theta))^1.5
696   </pre>
697  
698 + <p>
699 +
700   A perfectly isotropic scattering medium has a g parameter of 0, and
701   a highly directional material has a g parameter close to 1.
702   Fits to the g parameter may be found along with typical extinction
# Line 681 | Line 711 | cloud types in USGS meteorological tables.
711          0|3|6|7 [ rext gext bext [ ralb galb balb [ g ] ] ]
712   </pre>
713  
714 + <p>
715 +
716   There are two usual uses of the mist type.
717   One is to surround a beam from a spotlight or laser so that it is
718   visible during rendering.
# Line 799 | Line 831 | unless the line integrals consider enclosed geometry.
831  
832   <dd>
833          Trans2 is the anisotropic version of <a HREF="#Trans">trans</a>.  
834 <        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.
834 >        The string arguments  are  the same as for <a HREF="#Plastic2">plastic2</a>,
835 >        and the real arguments are the same as  for  trans  but  with  an  additional roughness value.
836  
837   <pre>
838          mod trans2 id
# Line 811 | Line 844 | unless the line integrals consider enclosed geometry.
844   <p>
845  
846   <dt>
847 +        <a NAME="Ashik2">
848 +        <b>Ashik2</b>
849 +        </a>
850 +
851 + <dd>
852 +        Ashik2 is the anisotropic reflectance model by Ashikhmin & Shirley.
853 +        The string arguments are the same as for <a HREF="#Plastic2">plastic2</a>, but the real
854 +        arguments have additional flexibility to specify the specular color.
855 +        Also, rather than roughness, specular power is used, which has no
856 +        physical meaning other than larger numbers are equivalent to a smoother
857 +        surface.
858 +        Unlike other material types, total reflectance is the sum of
859 +        diffuse and specular colors, and should be adjusted accordingly.
860 + <pre>
861 +        mod ashik2 id
862 +        4+ ux uy uz funcfile transform
863 +        0
864 +        8 dred dgrn dblu sred sgrn sblu u-power v-power
865 + </pre>
866 +
867 + <p>
868 +
869 + <dt>
870 +        <a NAME="WGMDfunc">
871 +        <b>WGMDfunc</b>
872 +        </a>
873 +
874 + <dd>
875 +        WGMDfunc is a more programmable version of <a HREF="#Trans2">trans2</a>,
876 +        with separate modifier paths and variables to control each component.
877 +        (WGMD stands for Ward-Geisler-Moroder-Duer, which is the basis for
878 +        this empirical model, similar to previous ones beside Ashik2.)
879 +        The specification of this material is given below.
880 + <pre>
881 +        mod WGMDfunc id
882 +        13+ rs_mod  rs  rs_urough rs_vrough
883 +            ts_mod  ts  ts_urough ts_vrough
884 +            td_mod
885 +            ux uy uz  funcfile  transform
886 +        0
887 +        9+  rfdif gfdif bfdif
888 +            rbdif gbdif bbdif
889 +            rtdif gtdif btdif
890 +            A10 ..
891 + </pre>
892 +
893 + <p>
894 +
895 + The sum of specular reflectance (<I>rs</I>), specular transmittance (<I>ts</I>),
896 + diffuse reflectance (<I>rfdif gfdif bfdif</I> for front and <I>rbdif gbdif bbdif</I> for back)
897 + and diffuse transmittance (<I>rtdif gtdif btdif</I>) should be less than 1 for each
898 + channel.
899 +
900 + <p>
901 +
902 + Unique to this material, separate modifier channels are
903 + provided for each component.
904 + The main modifier is used on the diffuse reflectance, both
905 + front and back.
906 + The <I>rs_mod</I> modifier is used for specular reflectance.
907 + If "void" is given for <I>rs_mod</I>,
908 + then the specular reflection color will be white.
909 + The special "inherit" keyword may also be given, in which case
910 + specular reflectance will share the main modifier.
911 + This behavior is replicated for the specular transmittance modifier
912 + <I>ts_mod</I>, which also has its own independent roughness expressions.
913 + Finally, the diffuse transmittance modifier is given as
914 + <I>td_mod</I>, which may also be "void" or "inherit".
915 + Note that any spectra or color for specular components must be
916 + carried by the named modifier(s).
917 +
918 + <p>
919 +
920 + The main advantage to this material over
921 + <a HREF="#BRTDfunc">BRTDfunc</a> and
922 + other programmable types described below is that the specular sampling is
923 + well-defined, so that all components are fully computed.
924 +
925 + <p>
926 +
927 + <dt>
928          <a NAME="Dielectric">
929          <b>Dielectric</b>
930          </a>
# Line 871 | Line 985 | unless the line integrals consider enclosed geometry.
985          tn = (sqrt(.8402528435+.0072522239*Tn*Tn)-.9166530661)/.0036261119/Tn
986   </pre>
987  
988 + <p>
989 +
990          Standard 88% transmittance glass  has  a  transmissivity  of 0.96.  
991          (A <a HREF="#Patterns">pattern</a> modifying glass will affect the transmissivity.)
992          If a fourth real argument is given,  it  is  interpreted as the index of refraction to use instead of 1.52.
# Line 902 | Line 1018 | unless the line integrals consider enclosed geometry.
1018          4+ red green blue spec A5 ..
1019   </pre>
1020  
1021 + <p>
1022 +
1023          The function refl takes four arguments, the x, y and z
1024          direction towards the incident light, and the solid angle
1025          subtended by the source.
# Line 943 | Line 1061 | unless the line integrals consider enclosed geometry.
1061          6+ red green blue rspec trans tspec A7 ..
1062   </pre>
1063  
1064 + <p>
1065 +
1066          Where trans is the total light transmitted and tspec is  the non-Lambertian  fraction of transmitted light.  
1067          The function brtd should integrate to 1 over each projected hemisphere.
1068  
# Line 970 | Line 1090 | unless the line integrals consider enclosed geometry.
1090               A10 ..
1091   </pre>
1092  
1093 + <p>
1094 +
1095          The variables rrefl, grefl and brefl specify the color coefficients  for  the ideal specular (mirror) reflection of the surface.  
1096          The variables rtrns, gtrns and btrns  specify  the color coefficients for the ideal specular transmission.  
1097          The functions rbrtd, gbrtd and bbrtd take the direction to the incident light (and its solid angle) and  
# Line 1014 | Line 1136 | unless the line integrals consider enclosed geometry.
1136          4+ red green blue spec A5 ..
1137   </pre>
1138  
1139 + <p>
1140 +
1141          The coordinate indices (x1, x2, etc.) are  themselves  functions  of  the  x,  y and z direction to the incident light, plus the solid angle
1142          subtended by the light source (usually ignored).
1143          The data function (func) takes five variables, the
# Line 1055 | Line 1179 | unless the line integrals consider enclosed geometry.
1179   <p>
1180  
1181   <dt>
1182 +        <a NAME="BSDF">
1183 +        <b>BSDF</b>
1184 +        </a>
1185 +
1186 + <dd>
1187 +        The BSDF material type loads an XML (eXtensible Markup Language)
1188 +        file describing a bidirectional scattering distribution function.
1189 +        Real arguments to this material may define additional
1190 +        diffuse components that augment the BSDF data.
1191 +        String arguments are used to define thickness for proxied
1192 +        surfaces and the &quot;up&quot; orientation for the material.
1193 +
1194 + <pre>
1195 +        mod BSDF id
1196 +        6+ thick BSDFfile ux uy uz funcfile transform
1197 +        0
1198 +        0|3|6|9
1199 +                rfdif gfdif bfdif
1200 +                rbdif gbdif bbdif
1201 +                rtdif gtdif btdif
1202 + </pre>
1203 +
1204 + <p>
1205 +        The first string argument is a &quot;thickness&quot; parameter that may be used
1206 +        to hide detail geometry being proxied by an aggregate BSDF material.
1207 +        If a view or shadow ray hits a BSDF proxy with non-zero thickness,
1208 +        it will pass directly through as if the surface were not there.
1209 +        Similar to the illum type, this permits direct viewing and
1210 +        shadow testing of complex geometry.
1211 +        The BSDF is used when a scattered (indirect) ray hits the surface,
1212 +        and any transmitted sample rays will be offset by the thickness amount
1213 +        to avoid the hidden geometry and gather samples from the other side.
1214 +        In this manner, BSDF surfaces can improve the results for indirect
1215 +        scattering from complex systems without sacrificing appearance or
1216 +        shadow accuracy.
1217 +        If the BSDF has transmission and back-side reflection data,
1218 +        a parallel BSDF surface may be
1219 +        placed slightly less than the given thickness away from the front surface
1220 +        to enclose the complex geometry on both sides.
1221 +        The sign of the thickness is important, as it indicates
1222 +        whether the proxied geometry is behind the BSDF
1223 +        surface (when thickness is positive) or in front (when
1224 +        thickness is negative).
1225 + <p>
1226 +        The second string argument is the name of the BSDF file,
1227 +        which is found in the usual auxiliary locations.  The
1228 +        following three string parameters name variables for an
1229 +        &quot;up&quot; vector, which together with the surface
1230 +        normal, define the local coordinate system that orients the
1231 +        BSDF.  These variables, along with the thickness, are defined
1232 +        in a function file given as the next string argument.  An
1233 +        optional transform is used to scale the thickness and
1234 +        reorient the up vector.
1235 + <p>
1236 +        If no real arguments are given, the BSDF is used by itself
1237 +        to determine reflection and transmission.  If there are at
1238 +        least 3 real arguments, the first triplet is an additional
1239 +        diffuse reflectance for the front side.  At least 6 real
1240 +        arguments adds diffuse reflectance to the rear side of the
1241 +        surface.  If there are 9 real arguments, the final triplet
1242 +        will be taken as an additional diffuse transmittance.  All
1243 +        diffuse components as well as the non-diffuse transmission
1244 +        are modified by patterns applied to this material.  The
1245 +        non-diffuse reflection from either side are unaffected.
1246 +        Textures perturb the effective surface normal in the usual
1247 +        way.
1248 + <p>
1249 +        The surface normal of this type is not altered to face the
1250 +        incoming ray, so the front and back BSDF reflections may
1251 +        differ.  (Transmission is identical front-to-back by physical
1252 +        law.) If back visibility is turned off during rendering and
1253 +        there is no transmission or back-side reflection, only then
1254 +        the surface will be invisible from behind.  Unlike other
1255 +        data-driven material types, the BSDF type is fully supported
1256 +        and all parts of the distribution are properly sampled.
1257 + <p>
1258 +
1259 + <dt>
1260 +        <a NAME="aBSDF">
1261 +        <b>aBSDF</b>
1262 +        </a>
1263 +
1264 + <dd>
1265 +        The aBSDF material is identical to the BSDF type with two
1266 +        important differences.  First, proxy geometry is not
1267 +        supported, so there is no thickness parameter.  Second, an
1268 +        aBSDF is assumed to have some specular through component
1269 +        (the &rsquo;a&rsquo; stands for &quot;aperture&quot;),
1270 +        which is treated specially during the direct calculation
1271 +        and when viewing the material.  Based on the BSDF data, the
1272 +        coefficient of specular transmission is determined and used
1273 +        for modifying unscattered shadow and view rays.
1274 +
1275 + <pre>
1276 +        mod aBSDF id
1277 +        5+ BSDFfile ux uy uz funcfile transform
1278 +        0
1279 +        0|3|6|9
1280 +             rfdif gfdif bfdif
1281 +             rbdif gbdif bbdif
1282 +             rtdif gtdif btdif
1283 + </pre>
1284 +
1285 + <p>
1286 +        If a material has no specular transmitted component, it is
1287 +        much better to use the BSDF type with a zero thickness
1288 +        than to use aBSDF.
1289 + <p>
1290 +
1291 + <dt>
1292          <a NAME="Antimatter">
1293          <b>Antimatter</b>
1294          </a>
# Line 1070 | Line 1304 | unless the line integrals consider enclosed geometry.
1304          0
1305   </pre>
1306  
1307 + <p>
1308 +
1309          The first modifier will also be used to shade  the  area  leaving the  antimatter  volume and entering the regular volume.  
1310          If mod1 is void, the antimatter volume is completely invisible.
1311          Antimatter  does  not  work  properly with the material type <a HREF="#Trans">&quot;trans&quot;</a>,
# Line 1119 | Line 1355 | A texture is a perturbation of the surface normal,  an
1355  
1356   <pre>
1357          mod texdata id
1358 <        8+ xfunc yfunc zfunc xdfname ydfname zdfname vfname x0 x1 .. xf
1358 >        8+ xfunc yfunc zfunc xdfname ydfname zdfname funcfile x0 x1 .. xf
1359          0
1360          n A1 A2 .. An
1361   </pre>
1362  
1363 + <p>
1364 +
1365   </dl>
1366  
1367   <p>
# Line 1263 | Line 1501 | A colorfunc is a procedurally  defined  color  pattern
1501                  [spacing]
1502   </pre>
1503  
1504 + <p>
1505 +
1506   or:
1507  
1508   <pre>
# Line 1300 | Line 1540 | or:
1540                  [spacing]
1541   </pre>
1542  
1543 + <p>
1544 +
1545   or:
1546  
1547   <pre>
# Line 1328 | Line 1570 | or:
1570          A section of text meant to  depict  a  picture, perhaps using a special purpose font such as hexbit4x1.fnt, calls for uniform  spacing.  
1571          Reasonable  magnitudes  for  proportional  spacing are between 0.1 (for tightly spaced characters) and 0.3 (for wide spacing).
1572  
1573 + <p>
1574 +
1575 + <dt>
1576 +        <a NAME="Spectrum">
1577 +        <b>Spectrum</b>
1578 +        </a>
1579 +
1580 + <dd>
1581 +        The spectrum primitive is the most basic type for introducing spectral
1582 +        color to a material.
1583 +        Since materials only provide RGB parameters, spectral patterns
1584 +        are the only way to superimpose wavelength-dependent behavior.
1585 +
1586 + <pre>
1587 +        mod spectrum id
1588 +        0
1589 +        0
1590 +        5+ nmA nmB s1 s2 .. sN
1591 + </pre>
1592 +
1593 + <p>
1594 +        The first two real arguments indicate the extrema of the
1595 +        spectral range in nanometers.
1596 +        Subsequent real values correspond to multipliers at each wavelength.
1597 +        The nmA wavelength may be greater or less than nmB,
1598 +        but they may not be equal, and their ordering matches
1599 +        the order of the spectral values.
1600 +        A minimum of 3 values must be given, which would act
1601 +        more or less the same as a constant RGB multiplier.
1602 +        As with RGB values, spectral quantities normally range between 0
1603 +        and 1 at each wavelength, or average to 1.0 against a standard
1604 +        sensitivity functions such as V(lambda).
1605 +        The best results obtain when the spectral range and number
1606 +        of samples match rendering options, though resampling will handle
1607 +        any differences, zero-filling wavelenths outside the nmA to nmB
1608 +        range.
1609 +        A warning will be issued if the given wavelength range does not
1610 +        adequately cover the visible spectrum.
1611 +
1612 + <p>
1613 +
1614 + <dt>
1615 +        <a NAME="Specfile">
1616 +        <b>Specfile</b>
1617 +        </a>
1618 +
1619 + <dd>
1620 +        The specfile primitive is equivalent to the spectrum type, but
1621 +        the wavelength range and values are contained in a 1-dimensional
1622 +        data file.
1623 +        This may be a more convenient way to specify a spectral color,
1624 +        especially one corresponding to a standard illuminant such as D65
1625 +        or a library of measured spectra.
1626 +
1627 + <pre>
1628 +        mod specfile id
1629 +        1 datafile
1630 +        0
1631 +        0
1632 + </pre>
1633 +
1634 + <p>
1635 +        As with the spectrum type, rendering wavelengths outside the defined
1636 +        range will be zero-filled.
1637 +        Unlike the spectrum type, the file may contain non-uniform samples.
1638 +
1639 + <p>
1640 +
1641 + <dt>
1642 +        <a NAME="Specfunc">
1643 +        <b>Specfunc</b>
1644 +        </a>
1645 +
1646 + <dd>
1647 +        The specfunc primitive offers dynamic control over a spectral
1648 +        pattern, similar to the colorfunc type.
1649 +
1650 + <pre>
1651 +        mod specfunc id
1652 +        2+ sfunc funcfile transform
1653 +        0
1654 +        2+ nmA nmB A3 ..
1655 + </pre>
1656 +
1657 + <p>
1658 +        Like the spectrum primitive, the wavelength range is specified
1659 +        in the first two real arguments, and additional real values are
1660 +        set in the evaluation context.
1661 +        This function is fed a wavelenth sample
1662 +        between nmA and nmB as its only argument,
1663 +        and it returns the corresponding spectral intensity.
1664 +
1665 + <dt>
1666 +       <a NAME="Specdata">
1667 +       <b>Specdata</b>
1668 +       </a>
1669 +
1670 + <dd>
1671 +        Specdata is like brightdata and colordata, but with more
1672 +        than 3 specular samples.
1673 +
1674 + <pre>
1675 +        mod specdata id
1676 +        3+n+
1677 +                func datafile
1678 +                funcfile x1 x2 .. xn transform
1679 +        0
1680 +        m A1 A2 .. Am
1681 + </pre>
1682 +
1683 + <p>
1684 +        The data file must have one more dimension than the coordinate
1685 +        variable count, as this final dimension corresponds to the covered
1686 +        spectrum.
1687 +        The starting and ending wavelengths are specified in "datafile"
1688 +        as well as the number of spectral samples.
1689 +        The function "func" will be called with two parameters, the
1690 +        interpolated spectral value for the current coordinate and the
1691 +        associated wavelength.
1692 +        If the spectrum is broken into 12 components, then 12 calls
1693 +        will be made to "func" for the relevant ray evaluation.
1694 +
1695 + <dt>
1696 +       <a NAME="Specpict">
1697 +       <b>Specpict</b>
1698 +       </a>
1699 +
1700 + <dd>
1701 +        Specpict is a special case of specdata, where the pattern is
1702 +        a hyperspectral image stored in the common-exponent file format.
1703 +        The dimensions of the image data are determined by the picture
1704 +        just as with the colorpict primitive.
1705 +
1706 + <pre>
1707 +        mod specpict id
1708 +        5+
1709 +                func specfile
1710 +                funcfile u v transform
1711 +        0
1712 +        m A1 A2 .. Am
1713 + </pre>
1714 +
1715 + <p>
1716 +        The function "func" is called with the interpolated pixel value
1717 +        and the wavelength sample in nanometers, the same as specdata,
1718 +        with as many calls made as there are components in "specfile".
1719 +
1720   </dl>
1721  
1722   <p>
# Line 1338 | Line 1727 | or:
1727   </h4>
1728  
1729   A mixture is a blend of one or more materials or textures and patterns.
1730 + Blended materials should not be light source types or virtual source types.
1731   The basic types are given below.
1732  
1733   <p>
# Line 1359 | Line 1749 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1749          n A1 A2 .. An
1750   </pre>
1751  
1752 + <p>
1753 +
1754          Foreground and background are modifier names that must be
1755          defined earlier in the scene description.
1756          If one of these is a material, then
# Line 1367 | Line 1759 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1759          which serves as a form of opacity control when used with a material.)
1760          Vname is the coefficient defined in funcfile that determines  the  influence  of  foreground.  
1761          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.
1762  
1763   <p>
1764  
# Line 1389 | Line 1779 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1779          m A1 A2 .. Am
1780   </pre>
1781  
1782 + <p>
1783 +
1784   <dt>
1785          <a NAME="Mixpict">
1786          <b>Mixpict</b>
# Line 1412 | Line 1804 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1804          arguments, the red, green and blue values
1805          corresponding to the pixel at (u,v).
1806  
1415 – </dl>
1807   <p>
1808  
1809   <dt>
# Line 1434 | Line 1825 | A mixfunc mixes  two  modifiers  procedurally.   It  i
1825                  [spacing]
1826   </pre>
1827  
1828 + <p>
1829 +
1830   or:
1831  
1832   <pre>
# Line 1449 | Line 1842 | or:
1842                  [spacing]
1843   </pre>
1844  
1845 + <p>
1846 +
1847   </dl>
1848  
1849   <p>
# Line 1493 | Line 1888 | An example function file is given below:
1888          cfunc(x) : 10*x / sqrt(x) ;
1889   </pre>
1890  
1891 + <p>
1892 +
1893   Many variables and functions are already defined by the program, and they are listed in the file rayinit.cal.  
1894   The following variables are particularly important:
1895  
# Line 1507 | Line 1904 | The following variables are particularly important:
1904                  arg(i)                  - i'th real argument
1905   </pre>
1906  
1907 + <p>
1908 +
1909   For mesh objects, the local surface coordinates are available:
1910  
1911   <pre>
1912                  Lu, Lv                  - local (u,v) coordinates
1913   </pre>
1914  
1915 + <p>
1916 +
1917   For BRDF types, the following variables are defined as well:
1918  
1919   <pre>
# Line 1521 | Line 1922 | For BRDF types, the following variables are defined as
1922                  CrP, CgP, CbP           - perturbed material color
1923   </pre>
1924  
1925 + <p>
1926 +
1927   A unique context is set up for each file so
1928   that  the  same variable may appear in different
1929   function files without conflict.  
# Line 1530 | Line 1933 | If no file is needed by a given primitive because all
1933   the  required  variables  are global,  
1934   a  period  (`.')  can be given in place of the file name.  
1935   It is also possible to give an expression instead
1936 < of a  straight  variable  name  in  a scene file,
1937 < although such expressions should be kept
1535 < simple if possible.
1536 < Also, functions (requiring parameters) must be given
1936 > of a  straight  variable  name  in  a scene file.
1937 > Functions (requiring parameters) must be given
1938   as names and not as expressions.
1939  
1940   <p>
# Line 1577 | Line 1978 | The basic data file format is as follows:
1978          DATA, later dimensions changing faster.
1979   </pre>
1980  
1981 + <p>
1982 +
1983   N is the number of  dimensions.  
1984   For  each  dimension,  the beginning  and  ending  coordinate  values and the dimension size is given.  
1985   Alternatively, individual coordinate  values can  be  given when the points are not evenly spaced.  
# Line 1605 | Line 2008 | All numbers are decimal integers:
2008           ...
2009   </pre>
2010  
2011 + <p>
2012 +
2013   The ASCII codes can appear in any order.  N is the number of vertices,  and  the  last  is automatically connected to the first.  
2014   Separate polygonal sections are joined by coincident sides.  
2015   The  character  coordinate  system is a square with lower left corner at (0,0), lower right at (255,0) and upper right at (255,255).
# Line 1680 | Line 2085 | The details of this process  are  not  important, but
2085   directs the use of a scene description.
2086   <ul>
2087   <li>
2088 < <a NAME="rview" HREF="../man_html/rview.1.html"><b>Rview</b></a>  is  ray-tracing  program  for  viewing  a  scene interactively.  
2089 < When  the user specifies a new perspective, rview quickly displays a rough image on the  terminal,  
2088 > <a NAME="rvu" HREF="../man_html/rvu.1.html"><b>Rvu</b></a>  is  ray-tracing  program  for  viewing  a  scene interactively.  
2089 > When  the user specifies a new perspective, rvu quickly displays a rough image on the  terminal,  
2090   then progressively increases the resolution as the user looks on.
2091   He can select a particular section of the image to  improve, or  move  to  a different view and start over.  
2092   This mode of interaction is useful for debugging scenes as well as determining the best view for a final image.
# Line 1716 | Line 2121 | Pictures may be displayed directly under X11 using the
2121   or converted a standard image format using one of the following
2122   <b>translators</b>:
2123          <ul>
2124 <        <li> <b>Ra_avs</b>
2125 <                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.
2124 >        <li> <a HREF="../man_html/ra_bmp.1.html"><b>Ra_bmp</b></a>
2125 >                converts to and from BMP image format.
2126          <li> <a HREF="../man_html/ra_ppm.1.html"><b>Ra_ppm</b></a>
2127                  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.
2128          <li> <a HREF="../man_html/ra_ps.1.html"><b>Ra_ps</b></a>
2129                  converts to PostScript color and greyscale formats.
2130          <li> <a HREF="../man_html/ra_rgbe.1.html"><b>Ra_rgbe</b></a>
# Line 1749 | Line 2148 | or converted a standard image format using one of the
2148   </h2>
2149  
2150   <pre>
2151 < The Radiance Software License, Version 1.0
2151 > The Radiance Software License, Version 2.0
2152  
2153 < Copyright (c) 1990 - 2002 The Regents of the University of California,
2154 < through Lawrence Berkeley National Laboratory.   All rights reserved.
2153 > Radiance v6.0 Copyright (c) 1990 to 2025, The Regents of the University of
2154 > California, through Lawrence Berkeley National Laboratory (subject to receipt
2155 > of any required approvals from the U.S. Dept. of Energy).  All rights reserved.
2156  
2157   Redistribution and use in source and binary forms, with or without
2158 < modification, are permitted provided that the following conditions
1759 < are met:
2158 > modification, are permitted provided that the following conditions are met:
2159  
2160 < 1. Redistributions of source code must retain the above copyright
2161 <        notice, this list of conditions and the following disclaimer.
2160 > (1) Redistributions of source code must retain the above copyright notice,
2161 > this list of conditions and the following disclaimer.
2162  
2163 < 2. Redistributions in binary form must reproduce the above copyright
2164 <      notice, this list of conditions and the following disclaimer in
2165 <      the documentation and/or other materials provided with the
1767 <      distribution.
2163 > (2) Redistributions in binary form must reproduce the above copyright
2164 > notice, this list of conditions and the following disclaimer in the
2165 > documentation and/or other materials provided with the distribution.
2166  
2167 < 3. The end-user documentation included with the redistribution,
2168 <          if any, must include the following acknowledgment:
2169 <            &quot;This product includes Radiance software
2170 <                (<a HREF="http://radsite.lbl.gov/">http://radsite.lbl.gov/</a>)
1773 <                developed by the Lawrence Berkeley National Laboratory
1774 <              (<a HREF="http://www.lbl.gov/">http://www.lbl.gov/</a>).&quot;
1775 <      Alternately, this acknowledgment may appear in the software itself,
1776 <      if and wherever such third-party acknowledgments normally appear.
2167 > (3) Neither the name of the University of California, Lawrence Berkeley
2168 > National Laboratory, U.S. Dept. of Energy nor the names of its contributors
2169 > may be used to endorse or promote products derived from this software
2170 > without specific prior written permission.
2171  
2172 < 4. The names &quot;Radiance,&quot; &quot;Lawrence Berkeley National Laboratory&quot;
2173 <      and &quot;The Regents of the University of California&quot; must
2174 <      not be used to endorse or promote products derived from this
2175 <      software without prior written permission. For written
2176 <      permission, please contact [email protected].
2172 > THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
2173 > AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
2174 > IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2175 > ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
2176 > LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
2177 > CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
2178 > SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
2179 > INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
2180 > CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
2181 > ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
2182 > POSSIBILITY OF SUCH DAMAGE.
2183  
2184 < 5. Products derived from this software may not be called &quot;Radiance&quot;,
2185 <      nor may &quot;Radiance&quot; appear in their name, without prior written
2186 <      permission of Lawrence Berkeley National Laboratory.
2187 <
2188 < THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
2189 < WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
2190 < OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
2191 < DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
2192 < ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
2193 < SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1794 < LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
1795 < USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
1796 < ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
1797 < OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
1798 < OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
1799 < SUCH DAMAGE.
2184 > You are under no obligation whatsoever to provide any bug fixes, patches,
2185 > or upgrades to the features, functionality or performance of the source
2186 > code ("Enhancements") to anyone; however, if you choose to make your
2187 > Enhancements available either publicly, or directly to Lawrence Berkeley
2188 > National Laboratory, without imposing a separate written license agreement
2189 > for such Enhancements, then you hereby grant the following license: a
2190 > non-exclusive, royalty-free perpetual license to install, use, modify,
2191 > prepare derivative works, incorporate into other computer software,
2192 > distribute, and sublicense such enhancements or derivative works thereof,
2193 > in binary and source code form.
2194   </pre>
2195  
2196 + <p>
2197 +
2198   <hr>
2199  
2200   <h2>
# Line 1824 | Line 2220 | Ecole  Polytechnique  Federale de Lausanne (EPFL Unive
2220   </h2>
2221   <p>
2222   <ul>
2223 +    <li>Ward, Gregory J., Bruno Bueno, David Geisler-Moroder,
2224 +      Lars O. Grobe, Jacob C. Jonsson, Eleanor
2225 +      S. Lee, Taoning Wang, Helen Rose Wilson,
2226 +      &quot;<a href="https://doi.org/10.1016/j.enbuild.2022.111890">Daylight
2227 +      Simulation Workflows Incorporating Measured Bidirectional
2228 +      Scattering Distribution Functions</a>&quot;
2229 +      <em>Energy &amp; Buildings</em>, Vol. 259, No. 11890, 2022.
2230 +    <li>Wang, Taoning, Gregory Ward, Eleanor Lee,
2231 +      &quot;<a href="https://authors.elsevier.com/a/1XQ0a1M7zGwT7v">Efficient
2232 +      modeling of optically-complex, non-coplanar exterior shading:
2233 +      Validation of matrix algebraic methods</a>&quot;
2234 +      <em>Energy & Buildings</em>, vol. 174, pp. 464-83, Sept. 2018.
2235 +    <li>Lee, Eleanor S., David Geisler-Moroder, Gregory Ward,
2236 +      &quot;<a href="https://eta.lbl.gov/sites/default/files/publications/solar_energy.pdf">Modeling
2237 +      the direct sun component in buildings using matrix
2238 +      algebraic approaches: Methods and
2239 +      validation</a>,&quot; <em>Solar Energy</em>,
2240 +      vol. 160, 15 January 2018, pp 380-395.
2241 +    <li>Narain, Rahul, Rachel A. Albert, Abdullah Bulbul,
2242 +       Gregory J. Ward, Marty Banks, James F. O'Brien,
2243 +       &quot;<a href="http://graphics.berkeley.edu/papers/Narain-OPI-2015-08/index.html">Optimal
2244 +       Presentation of Imagery with Focus
2245 +       Cues on Multi-Plane Displays</a>,&quot;
2246 +       <em>SIGGRAPH 2015</em>.
2247 +    <li>Ward, Greg, Murat Kurt, and Nicolas Bonneel,
2248 +        &quot;<a href="papers/WMAM14_Tensor_Tree_Representation.pdf">Reducing
2249 +        Anisotropic BSDF Measurement to Common Practice</a>,&quot;
2250 +        <em>Workshop on Material Appearance Modeling</em>, 2014.
2251 +    <li>Banks, Martin, Abdullah Bulbul, Rachel Albert, Rahul Narain,
2252 +        James F. O'Brien, Gregory Ward,
2253 +        &quot;<a href="http://graphics.berkeley.edu/papers/Banks-TPO-2014-05/index.html">The
2254 +        Perception of Surface Material from Disparity and Focus Cues</a>,&quot;
2255 +        <em>VSS 2014</em>.
2256 +    <li>McNeil, A., C.J. Jonsson, D. Appelfeld, G. Ward, E.S. Lee,
2257 +        &quot;<a href="http://gaia.lbl.gov/btech/papers/4414.pdf">
2258 +        A validation of a ray-tracing tool used to generate
2259 +        bi-directional scattering distribution functions for
2260 +        complex fenestration systems</a>,&quot;
2261 +        <em>Solar Energy</em>, 98, 404-14,
2262 +        November 2013.
2263 +    <li>Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson,
2264 +        &quot;<a href="http://gaia.lbl.gov/btech/papers/4414.pdf">Simulating
2265 +        the Daylight Performance of Complex Fenestration Systems
2266 +        Using Bidirectional Scattering Distribution Functions within
2267 +        Radiance</a>,&quot;
2268 +        <em>Leukos</em>, 7(4)
2269 +        April 2011.
2270 +    <li>Cater, Kirsten, Alan Chalmers, Greg Ward,
2271 +        &quot;<a href="http://www.anyhere.com/gward/papers/egsr2003.pdf">Detail to Attention:
2272 +        Exploiting Visual Tasks for Selective Rendering</a>,&quot;
2273 +        <em>Eurographics Symposium
2274 +        on Rendering 2003</em>, June 2003.
2275      <li>Ward, Greg, Elena Eydelberg-Vileshin,
2276 <        ``<a HREF="papers/egwr02/index.html">Picture Perfect RGB
2277 <        Rendering Using Spectral Prefiltering and Sharp Color Primaries</a>,''
2276 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/egwr02/index.html">Picture Perfect RGB
2277 >        Rendering Using Spectral Prefiltering and Sharp Color Primaries</a>,&quot;
2278          Thirteenth Eurographics Workshop on Rendering (2002),
2279          P. Debevec and S. Gibson (Editors), June 2002.
2280      <li>Ward, Gregory,
2281 <        ``<a HREF="papers/cic01.pdf">High Dynamic Range Imaging</a>,''
2281 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/cic01.pdf">High Dynamic Range Imaging</a>,&quot;
2282          Proceedings of the Ninth Color Imaging Conference, November 2001.
2283      <li>Ward, Gregory and Maryann Simmons,
2284 <        ``<a HREF="papers/tog99.pdf">
2284 >        &quot;<a HREF="http://www.anyhere.com/gward/papers/tog99.pdf">
2285          The Holodeck Ray Cache: An Interactive Rendering System for Global Illumination in Nondiffuse
2286 <        Environments</a>,'' ACM Transactions on Graphics, 18(4):361-98, October 1999.
2287 <    <li>Larson, G.W., ``<a HREF="papers/ewp98.pdf">The Holodeck: A Parallel
2288 <        Ray-caching Rendering System</a>,'' Proceedings of the Second
2286 >        Environments</a>,&quot; ACM Transactions on Graphics, 18(4):361-98, October 1999.
2287 >    <li>Larson, G.W., &quot;<a HREF="http://www.anyhere.com/gward/papers/ewp98.pdf">The Holodeck: A Parallel
2288 >        Ray-caching Rendering System</a>,&quot; Proceedings of the Second
2289          Eurographics Workshop on Parallel Graphics and Visualisation,
2290          September 1998.
2291      <li>Larson, G.W. and R.A. Shakespeare,
2292 <        <a HREF="../book/index.html"><em>Rendering with Radiance:
2292 >        <a HREF="http://radsite.lbl.gov/radiance/book/index.html"><em>Rendering with Radiance:
2293          the Art and Science of Lighting Visualization</em></a>,
2294          Morgan Kaufmann Publishers, 1998.
2295      <li>Larson, G.W., H. Rushmeier, C. Piatko,
2296 <        ``<a HREF="../papers/lbnl39882/tonemap.pdf">A Visibility
2296 >        &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/lbnl39882/tonemap.pdf">A Visibility
2297          Matching Tone Reproduction Operator for
2298 <        High Dynamic Range Scenes</a>,'' LBNL Technical Report 39882,
2298 >        High Dynamic Range Scenes</a>,&quot; LBNL Technical Report 39882,
2299          January 1997.
2300 <    <li>Ward, G., ``<a HREF="../papers/erw95.1/paper.html">Making
2301 <        Global Illumination User-Friendly</a>,'' Sixth
2300 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw95.1/paper.html">Making
2301 >        Global Illumination User-Friendly</a>,&quot; Sixth
2302          Eurographics Workshop on Rendering, Springer-Verlag,
2303          Dublin, Ireland, June 1995.</li>
2304      <li>Rushmeier, H., G. Ward, C. Piatko, P. Sanders, B. Rust,
2305 <        ``<a HREF="http://radsite.lbl.gov/mgf/compare.html">
2305 >        &quot;<a HREF="http://radsite.lbl.gov/mgf/compare.html">
2306          Comparing Real and Synthetic Images: Some Ideas about
2307 <        Metrics</a>,'' Sixth Eurographics Workshop on Rendering,
2307 >        Metrics</a>,&quot; Sixth Eurographics Workshop on Rendering,
2308          Springer-Verlag, Dublin, Ireland, June 1995.</li>
2309 <    <li>Ward, G., ``<a HREF="../papers/sg94.1/paper.html">The RADIANCE
2310 <        Lighting Simulation and Rendering System</a>,'' <em>Computer
2309 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.1/paper.html">The RADIANCE
2310 >        Lighting Simulation and Rendering System</a>,&quot; <em>Computer
2311          Graphics</em>, July 1994.</li>
2312 <    <li>Rushmeier, H., G. Ward, ``<a HREF="../papers/sg94.2/energy.html">Energy
2313 <        Preserving Non-Linear Filters</a>,'' <em>Computer
2312 >    <li>Rushmeier, H., G. Ward, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg94.2/energy.html">Energy
2313 >        Preserving Non-Linear Filters</a>,&quot; <em>Computer
2314          Graphics</em>, July 1994.</li>
2315 <    <li>Ward, G., ``A Contrast-Based Scalefactor for Luminance
2316 <        Display,'' <em>Graphics Gems IV</em>, Edited by Paul Heckbert,
2315 >    <li>Ward, G., &quot;A Contrast-Based Scalefactor for Luminance
2316 >        Display,&quot; <em>Graphics Gems IV</em>, Edited by Paul Heckbert,
2317          Academic Press 1994.</li>
2318 <    <li>Ward, G., ``<a HREF="../papers/sg92/paper.html">Measuring and
2319 <        Modeling Anisotropic Reflection</a>,'' <em>Computer
2318 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg92/paper.html">Measuring and
2319 >        Modeling Anisotropic Reflection</a>,&quot; <em>Computer
2320          Graphics</em>, Vol. 26, No. 2, July 1992. </li>
2321 <    <li>Ward, G., P. Heckbert, ``<a HREF="../papers/erw92/paper.html">Irradiance
2322 <        Gradients</a>,'' Third Annual Eurographics Workshop on
2321 >    <li>Ward, G., P. Heckbert, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw92/paper.html">Irradiance
2322 >        Gradients</a>,&quot; Third Annual Eurographics Workshop on
2323          Rendering, Springer-Verlag, May 1992. </li>
2324 <    <li>Ward, G., ``<a HREF="../papers/erw91/erw91.html">Adaptive Shadow
2325 <        Testing for Ray Tracing</a>'' Photorealistic Rendering in
2324 >    <li>Ward, G., &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/erw91/erw91.html">Adaptive Shadow
2325 >        Testing for Ray Tracing</a>&quot; Photorealistic Rendering in
2326          Computer Graphics, proceedings of 1991 Eurographics
2327          Rendering Workshop, edited by P. Brunet and F.W. Jansen,
2328          Springer-Verlag. </li>
2329 <    <li>Ward, G., ``Visualization,'' <em>Lighting Design and
2329 >    <li>Ward, G., &quot;Visualization,&quot; <em>Lighting Design and
2330          Application</em>, Vol. 20, No. 6, June 1990. </li>
2331 <    <li>Ward, G., F. Rubinstein, R. Clear, ``<a HREF="../papers/sg88/paper.html">A Ray Tracing Solution for
2332 <        Diffuse Interreflection</a>,'' <em>Computer Graphics</em>,
2331 >    <li>Ward, G., F. Rubinstein, R. Clear, &quot;<a HREF="http://radsite.lbl.gov/radiance/papers/sg88/paper.html">A Ray Tracing Solution for
2332 >        Diffuse Interreflection</a>,&quot; <em>Computer Graphics</em>,
2333          Vol. 22, No. 4, August 1988. </li>
2334 <    <li>Ward, G., F. Rubinstein, ``A New Technique for Computer
2335 <        Simulation of Illuminated Spaces,'' <em>Journal of the
2334 >    <li>Ward, G., F. Rubinstein, &quot;A New Technique for Computer
2335 >        Simulation of Illuminated Spaces,&quot; <em>Journal of the
2336          Illuminating Engineering Society</em>, Vol. 17, No. 1,
2337          Winter 1988. </li>
2338   </ul>
# Line 1922 | Line 2370 | SURFACES       MATERIALS       TEXTURES        PATTERNS        MIXTURES</h4>
2370                  <a HREF="#Plasdata">Plasdata</a>
2371                  <a HREF="#Metdata">Metdata</a>
2372                  <a HREF="#Transdata">Transdata</a>
2373 +                <a HREF="#BSDF">BSDF</a>
2374                  <a HREF="#Antimatter">Antimatter</a>
2375                                  
2376   </pre>

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