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.\" RCSid "$Id" |
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.\" RCSid "$Id$" |
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.\" Print using the -ms macro package |
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.DA 1/20/99 |
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.DA 12/09/2024 |
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.LP |
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.tl """Copyright \(co 1996 Regents, University of California |
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.tl """Copyright \(co 2024 Regents, University of California |
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.sp 2 |
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.TL |
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The |
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.br |
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Synthetic Imaging System |
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.AU |
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< |
Greg Ward |
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Building Technologies Department |
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.br |
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Lawrence Berkeley Laboratory |
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.br |
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1 Cyclotron Rd. |
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1 Cyclotron Rd., MS 90-3111 |
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.br |
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Berkeley, CA 94720 |
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– |
.br |
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– |
(510) 486-4757 |
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.NH 1 |
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Introduction |
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|
.PP |
47 |
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is a variation of |
48 |
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.I rpict |
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that computes and displays images interactively. |
50 |
+ |
Other programs (not shown) connect many of these elements together, |
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such as the executive programs |
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+ |
.I rad |
53 |
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and |
54 |
+ |
.I ranimate, |
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the interactive rendering program |
56 |
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.I rholo, |
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and the animation program |
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+ |
.I ranimove. |
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+ |
The program |
60 |
+ |
.I obj2mesh |
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acts as both a converter and scene compiler, converting a Wavefront .OBJ |
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file into a compiled mesh octree for efficient rendering. |
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.PP |
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A scene description file lists the surfaces and materials |
65 |
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that make up a specific environment. |
66 |
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The current surface types are spheres, polygons, cones, |
67 |
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and cylinders. |
68 |
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They can be made from materials such as plastic, metal, |
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and glass. |
70 |
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Light sources can be distant disks as well as local spheres, discs and |
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polygons. |
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that make up a specific environment. |
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The current surface types are spheres, polygons, cones, and cylinders. |
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> |
There is also a composite surface type, called mesh, and a pseudosurface |
68 |
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type, called instance, which facilitates very complex geometries. |
69 |
> |
Surfaces can be made from materials such as plastic, metal, and glass. |
70 |
> |
Light sources can be distant disks as well as local spheres, disks |
71 |
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and polygons. |
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|
.PP |
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From a three-dimensional scene description and a specified view, |
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.I rpict |
95 |
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# comment |
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|
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modifier type identifier |
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< |
n S1 S2 S3 .. Sn |
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n S1 S2 "S 3" .. Sn |
99 |
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0 |
100 |
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m R1 R2 R3 .. Rm |
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|
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Thus, the same identifier may be used repeatedly, and each new |
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definition will apply to the primitives following it. |
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.FE |
126 |
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An identifier can be any string (i.e. sequence of non-blank |
116 |
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characters). |
126 |
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An identifier can be any string (i.e., any sequence of non-white characters). |
127 |
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The |
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.I arguments |
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associated with a primitive can be strings or real numbers. |
130 |
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The first integer following the identifier is the number |
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of string arguments, and it is followed by the arguments themselves |
132 |
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(separated by white space). |
132 |
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(separated by white space or enclosed in quotes). |
133 |
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The next integer is the number of integer arguments, and is followed |
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by the integer arguments. |
135 |
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(There are currently no primitives that use them, however.) |
152 |
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A command may be continued over multiple lines using a backslash, `\\', |
153 |
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to escape the newline. |
154 |
|
.PP |
155 |
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Blank space is generally ignored, except as a separator. |
155 |
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White space is generally ignored, except as a separator. |
156 |
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The exception is the newline character after a command or comment. |
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Commands, comments and primitives may appear in any combination, so long |
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as they are not intermingled. |
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Primitive Types |
161 |
|
.PP |
162 |
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Primitives can be surfaces, materials, textures or patterns. |
163 |
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Modifiers can be materials, textures or patterns. |
163 |
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Modifiers can be materials, mixtures, textures or patterns. |
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|
Simple surfaces must have one material in their modifier list. |
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.NH 3 |
166 |
|
Surfaces |
233 |
|
.LP |
234 |
|
.UL Cup |
235 |
|
.PP |
236 |
< |
A cup is an inverted cone (i.e. has an inward surface normal). |
236 |
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A cup is an inverted cone (i.e., has an inward surface normal). |
237 |
|
.LP |
238 |
|
.UL Cylinder |
239 |
|
.PP |
272 |
|
A mesh is a compound surface, made up of many triangles and |
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an octree data structure to accelerate ray intersection. |
274 |
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It is typically converted from a Wavefront .OBJ file using the |
275 |
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obj2mesh program. |
275 |
> |
.I obj2mesh |
276 |
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program. |
277 |
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.DS |
278 |
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mod mesh id |
279 |
|
1+ meshfile transform |
294 |
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available memory. |
295 |
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In addition, the mesh primitive can have associated (u,v) coordinates |
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for pattern and texture mapping. |
297 |
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These are made available to function files via the Lu and Lu variables. |
297 |
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These are made available to function files via the Lu and Lv variables. |
298 |
|
.LP |
299 |
|
.UL Instance |
300 |
|
.PP |
332 |
|
.LP |
333 |
|
.UL Light |
334 |
|
.PP |
335 |
< |
Light is the basic material for self-luminous surfaces (i.e. light |
335 |
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Light is the basic material for self-luminous surfaces (i.e., light |
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sources). |
337 |
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In addition to the source surface type, spheres, discs (rings with zero |
338 |
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inner radius), cylinders (provided they are long enough), and |
392 |
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As well as radiance, the full cone angle (in degrees) |
393 |
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and orientation (output direction) vector are given. |
394 |
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The length of the orientation vector is the distance |
395 |
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of the effective focus behind the source center (i.e. the focal length). |
395 |
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of the effective focus behind the source center (i.e., the focal length). |
396 |
|
.DS |
397 |
|
mod spotlight id |
398 |
|
0 |
402 |
|
.LP |
403 |
|
.UL Mirror |
404 |
|
.PP |
405 |
< |
Mirror is used for planar surfaces that produce secondary |
405 |
> |
Mirror is used for planar surfaces that produce virtual |
406 |
|
source reflections. |
407 |
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This material should be used sparingly, as it may cause the light |
408 |
|
source calculation to blow up if it is applied to many small surfaces. |
426 |
|
.UL Prism1 |
427 |
|
.PP |
428 |
|
The prism1 material is for general light redirection from prismatic |
429 |
< |
glazings, generating secondary light sources. |
430 |
< |
It can only be used to modify a planar surface (i.e. a polygon or disk) |
429 |
> |
glazings, generating virtual light sources. |
430 |
> |
It can only be used to modify a planar surface (i.e., a polygon or disk) |
431 |
|
and should not result in either light concentration or scattering. |
432 |
|
The new direction of the ray can be on either side of the material, |
433 |
|
and the definitions must have the correct bidirectional properties |
434 |
< |
to work properly with secondary light sources. |
434 |
> |
to work properly with virtual light sources. |
435 |
|
The arguments give the coefficient for the redirected light |
436 |
|
and its direction. |
437 |
|
.DS |
491 |
|
The scattering eccentricity parameter will likewise override the global |
492 |
|
setting if it is present. |
493 |
|
Scattering eccentricity indicates how much scattered light favors the |
494 |
< |
forward direction, as fit by the Heyney-Greenstein function: |
494 |
> |
forward direction, as fit by the Henyey-Greenstein function: |
495 |
|
.DS |
496 |
|
P(theta) = (1 - g*g) / (1 + g*g - 2*g*cos(theta))^1.5 |
497 |
|
.DE |
580 |
|
These three expressions (separated by white space) are evaluated in |
581 |
|
the context of the function file |
582 |
|
.I funcfile. |
583 |
< |
If no function file is required (i.e. no special variables or |
583 |
> |
If no function file is required (i.e., no special variables or |
584 |
|
functions are required), a period (`.') may be given in its |
585 |
|
place. |
586 |
|
(See the discussion of Function Files in the Auxiliary Files section). |
622 |
|
8 red green blue spec urough vrough trans tspec |
623 |
|
.DE |
624 |
|
.LP |
625 |
+ |
.UL Ashik2 |
626 |
+ |
.PP |
627 |
+ |
Ashik2 is the anisotropic reflectance model by Ashikhmin & Shirley. |
628 |
+ |
The string arguments are the same as for plastic2, but the real |
629 |
+ |
arguments have additional flexibility to specify the specular color. |
630 |
+ |
Also, rather than roughness, specular power is used, which has no |
631 |
+ |
physical meaning other than larger numbers are equivalent to a smoother |
632 |
+ |
surface. |
633 |
+ |
Unlike other material types, total reflectance is the sum of |
634 |
+ |
diffuse and specular colors, and should be adjusted accordingly. |
635 |
+ |
.DS |
636 |
+ |
mod ashik2 id |
637 |
+ |
4+ ux uy uz funcfile transform |
638 |
+ |
0 |
639 |
+ |
8 dred dgrn dblu sred sgrn sblu u-power v-power |
640 |
+ |
.DE |
641 |
+ |
.LP |
642 |
+ |
.UL WGMDfunc |
643 |
+ |
.PP |
644 |
+ |
WGMDfunc is a more programmable version of trans2, |
645 |
+ |
with separate modifier paths and variables to control each component. |
646 |
+ |
(WGMD stands for Ward-Geisler-Moroder-Duer, which is the basis for |
647 |
+ |
this empirical model, similar to the previous ones beside Ashik2.)\0 |
648 |
+ |
The specification of this material is given below. |
649 |
+ |
.DS |
650 |
+ |
mod WGMDfunc id |
651 |
+ |
13+ rs_mod rs rs_urough rs_vrough |
652 |
+ |
ts_mod ts ts_urough ts_vrough |
653 |
+ |
td_mod |
654 |
+ |
ux uy uz funcfile transform |
655 |
+ |
0 |
656 |
+ |
9+ rfdif gfdif bfdif |
657 |
+ |
rbdif gbdif bbdif |
658 |
+ |
rtdif gtdif btdif |
659 |
+ |
A10 .. |
660 |
+ |
.DE |
661 |
+ |
The sum of specular reflectance ( |
662 |
+ |
.I rs |
663 |
+ |
), specular transmittance ( |
664 |
+ |
.I ts |
665 |
+ |
), diffuse reflectance ( |
666 |
+ |
.I "rfdif gfdif bfdif" |
667 |
+ |
for front and |
668 |
+ |
.I "rbdif gbdif bbdif" |
669 |
+ |
for back) |
670 |
+ |
and diffuse transmittance ( |
671 |
+ |
.I "rtdif gtdif btdif" |
672 |
+ |
) should be less than 1 for each |
673 |
+ |
channel. |
674 |
+ |
.PP |
675 |
+ |
Unique to this material, separate modifier channels are |
676 |
+ |
provided for each component. |
677 |
+ |
The main modifier is used on the diffuse reflectance, both |
678 |
+ |
front and back. |
679 |
+ |
The |
680 |
+ |
.I rs_mod |
681 |
+ |
modifier is used for specular reflectance. |
682 |
+ |
If "void" is given for |
683 |
+ |
.I rs_mod, |
684 |
+ |
then the specular reflection color will be white. |
685 |
+ |
The special "inherit" keyword may also be given, in which case |
686 |
+ |
specular reflectance will share the main modifier. |
687 |
+ |
This behavior is replicated for the specular transmittance modifier |
688 |
+ |
.I ts_mod, |
689 |
+ |
which has its own independent roughness expressions. |
690 |
+ |
Finally, the diffuse transmittance modifier is given as |
691 |
+ |
.I td_mod, |
692 |
+ |
which may also be "void" or "inherit". |
693 |
+ |
Note that any spectra or color for specular components must be |
694 |
+ |
carried by the named modifier(s). |
695 |
+ |
.PP |
696 |
+ |
The main advantage to this material over BRTDfunc and |
697 |
+ |
other programmable types described below is that the specular sampling is |
698 |
+ |
well-defined, so that all components are fully computed. |
699 |
+ |
.LP |
700 |
|
.UL Dielectric |
701 |
|
.PP |
702 |
|
A dielectric material is transparent, and it refracts light |
940 |
|
6+ red green blue rspec trans tspec A7 .. |
941 |
|
.DE |
942 |
|
.LP |
943 |
+ |
.UL BSDF |
944 |
+ |
.PP |
945 |
+ |
The BSDF material type loads an XML (eXtensible Markup Language) |
946 |
+ |
file describing a bidirectional scattering distribution function. |
947 |
+ |
Real arguments to this material may define additional |
948 |
+ |
diffuse components that augment the BSDF data. |
949 |
+ |
String arguments are used to define thickness for proxied |
950 |
+ |
surfaces and the "up" orientation for the material. |
951 |
+ |
.DS |
952 |
+ |
mod BSDF id |
953 |
+ |
6+ thick BSDFfile ux uy uz funcfile transform |
954 |
+ |
0 |
955 |
+ |
0|3|6|9 |
956 |
+ |
rfdif gfdif bfdif |
957 |
+ |
rbdif gbdif bbdif |
958 |
+ |
rtdif gtdif btdif |
959 |
+ |
.DE |
960 |
+ |
The first string argument is a "thickness" parameter that may be used |
961 |
+ |
to hide detail geometry being proxied by an aggregate BSDF material. |
962 |
+ |
If a view or shadow ray hits a BSDF proxy with non-zero thickness, |
963 |
+ |
it will pass directly through as if the surface were not there. |
964 |
+ |
Similar to the illum type, this permits direct viewing and |
965 |
+ |
shadow testing of complex geometry. |
966 |
+ |
The BSDF is used when a scattered (indirect) ray hits the surface, |
967 |
+ |
and any transmitted sample rays will be offset by the thickness amount |
968 |
+ |
to avoid the hidden geometry and gather samples from the other side. |
969 |
+ |
In this manner, BSDF surfaces can improve the results for indirect |
970 |
+ |
scattering from complex systems without sacrificing appearance or |
971 |
+ |
shadow accuracy. |
972 |
+ |
If the BSDF has transmission and back-side reflection data, |
973 |
+ |
a parallel BSDF surface may be |
974 |
+ |
placed slightly less than the given thickness away from the front surface |
975 |
+ |
to enclose the complex geometry on both sides. |
976 |
+ |
The sign of the thickness is important, as it indicates whether the |
977 |
+ |
proxied geometry is behind the BSDF surface (when thickness is positive) |
978 |
+ |
or in front (when thickness is negative). |
979 |
+ |
.LP |
980 |
+ |
The second string argument is the name of the BSDF file, which is |
981 |
+ |
found in the usual auxiliary locations. |
982 |
+ |
The following three string parameters name variables for an "up" vector, |
983 |
+ |
which together with the surface normal, define the |
984 |
+ |
local coordinate system that orients the BSDF. |
985 |
+ |
These variables, along with the thickness, are defined in a function |
986 |
+ |
file given as the next string argument. |
987 |
+ |
An optional transform is used to scale the thickness and reorient the up vector. |
988 |
+ |
.LP |
989 |
+ |
If no real arguments are given, the BSDF is used by itself to determine |
990 |
+ |
reflection and transmission. |
991 |
+ |
If there are at least 3 real arguments, the first triplet is an |
992 |
+ |
additional diffuse reflectance for the front side. |
993 |
+ |
At least 6 real arguments adds diffuse reflectance to the rear side of the surface. |
994 |
+ |
If there are 9 real arguments, the final triplet will be taken as an additional |
995 |
+ |
diffuse transmittance. |
996 |
+ |
All diffuse components as well as the non-diffuse transmission are |
997 |
+ |
modified by patterns applied to this material. |
998 |
+ |
The non-diffuse reflection from either side are unaffected. |
999 |
+ |
Textures perturb the effective surface normal in the usual way. |
1000 |
+ |
.LP |
1001 |
+ |
The surface normal of this type is not altered to face the incoming ray, |
1002 |
+ |
so the front and back BSDF reflections may differ. |
1003 |
+ |
(Transmission is identical front-to-back by physical law.)\0 |
1004 |
+ |
If back visibility is turned off during rendering and there is no |
1005 |
+ |
transmission or back-side reflection, only then the surface will be |
1006 |
+ |
invisible from behind. |
1007 |
+ |
Unlike other data-driven material types, the BSDF type is fully |
1008 |
+ |
supported and all parts of the distribution are properly sampled. |
1009 |
+ |
.LP |
1010 |
+ |
.UL aBSDF |
1011 |
+ |
.PP |
1012 |
+ |
The aBSDF material is identical to the BSDF type with two important |
1013 |
+ |
differences. |
1014 |
+ |
First, proxy geometry is not supported, so there is no thickness parameter. |
1015 |
+ |
Second, an aBSDF is assumed to have some specular through component |
1016 |
+ |
(the 'a' stands for "aperture"), which |
1017 |
+ |
is treated specially during the direct calculation and when viewing the |
1018 |
+ |
material. |
1019 |
+ |
Based on the BSDF data, the coefficient of specular transmission is |
1020 |
+ |
determined and used for modifying unscattered shadow and view rays. |
1021 |
+ |
.DS |
1022 |
+ |
mod aBSDF id |
1023 |
+ |
5+ BSDFfile ux uy uz funcfile transform |
1024 |
+ |
0 |
1025 |
+ |
0|3|6|9 |
1026 |
+ |
rfdif gfdif bfdif |
1027 |
+ |
rbdif gbdif bbdif |
1028 |
+ |
rtdif gtdif btdif |
1029 |
+ |
.DE |
1030 |
+ |
.LP |
1031 |
+ |
If a material has no specular transmitted component, it is much better |
1032 |
+ |
to use the BSDF type with a zero thickness than to use aBSDF. |
1033 |
+ |
.LP |
1034 |
|
.UL Antimatter |
1035 |
|
.PP |
1036 |
|
Antimatter is a material that can "subtract" volumes from other volumes. |
1045 |
|
The first modifier will also be used to shade the area leaving the |
1046 |
|
antimatter volume and entering the regular volume. |
1047 |
|
If mod1 is void, the antimatter volume is completely invisible. |
1048 |
< |
Antimatter does not work properly with the material type "trans", |
1049 |
< |
and multiple antimatter surfaces should be disjoint. |
1048 |
> |
If shading is desired at antimatter surfaces, it is important |
1049 |
> |
that the related volumes are closed with outward-facing normals. |
1050 |
> |
Antimatter surfaces should not intersect with other antimatter boundaries, |
1051 |
> |
and it is unwise to use the same modifier in nested antimatter volumes. |
1052 |
|
The viewpoint must be outside all volumes concerned for a correct |
1053 |
|
rendering. |
1054 |
|
.NH 3 |
1252 |
|
font such as hexbit4x1.fnt, calls for uniform spacing. |
1253 |
|
Reasonable magnitudes for proportional spacing are |
1254 |
|
between 0.1 (for tightly spaced characters) and 0.3 (for wide spacing). |
1255 |
+ |
.LP |
1256 |
+ |
.UL Spectrum |
1257 |
+ |
.PP |
1258 |
+ |
The spectrum primitive is the most basic type for introducing spectral |
1259 |
+ |
color to a material. |
1260 |
+ |
Since materials only provide RGB parameters, spectral patterns |
1261 |
+ |
are the only way to superimpose wavelength-dependent behavior. |
1262 |
+ |
.DS |
1263 |
+ |
mod spectrum id |
1264 |
+ |
0 |
1265 |
+ |
0 |
1266 |
+ |
5+ nmA nmB s1 s2 .. sN |
1267 |
+ |
.DE |
1268 |
+ |
The first two real arguments indicate the extrema of the |
1269 |
+ |
spectral range in nanometers. |
1270 |
+ |
Subsequent real values correspond to multipliers at each wavelength. |
1271 |
+ |
The nmA wavelength may be greater or less than nmB, |
1272 |
+ |
but they may not be equal, and their ordering matches |
1273 |
+ |
the order of the spectral values. |
1274 |
+ |
A minimum of 3 values must be given, which would act |
1275 |
+ |
more or less the same as a constant RGB multiplier. |
1276 |
+ |
As with RGB values, spectral quantities normally range between 0 |
1277 |
+ |
and 1 at each wavelength, or average to 1.0 against a standard |
1278 |
+ |
sensitivity functions such as V(lambda). |
1279 |
+ |
The best results obtain when the spectral range and number |
1280 |
+ |
of samples match rendering options, though resampling will handle |
1281 |
+ |
any differences, zero-filling wavelenths outside the nmA to nmB |
1282 |
+ |
range. |
1283 |
+ |
A warning will be issued if the given wavelength range does not |
1284 |
+ |
adequately cover the visible spectrum. |
1285 |
+ |
.LP |
1286 |
+ |
.UL Specfile |
1287 |
+ |
.PP |
1288 |
+ |
The specfile primitive is equivalent to the spectrum type, but |
1289 |
+ |
the wavelength range and values are contained in a 1-dimensional |
1290 |
+ |
data file. |
1291 |
+ |
This may be a more convenient way to specify a spectral color, |
1292 |
+ |
especially one corresponding to a standard illuminant such as D65 |
1293 |
+ |
or a library of measured spectra. |
1294 |
+ |
.DS |
1295 |
+ |
mod specfile id |
1296 |
+ |
1 datafile |
1297 |
+ |
0 |
1298 |
+ |
0 |
1299 |
+ |
.DE |
1300 |
+ |
As with the spectrum type, rendering wavelengths outside the defined |
1301 |
+ |
range will be zero-filled. |
1302 |
+ |
Unlike the spectrum type, the file may contain non-uniform samples. |
1303 |
+ |
.LP |
1304 |
+ |
.UL Specfunc |
1305 |
+ |
.PP |
1306 |
+ |
The specfunc primitive offers dynamic control over a spectral |
1307 |
+ |
pattern, similar to the colorfunc type. |
1308 |
+ |
.DS |
1309 |
+ |
mod specfunc id |
1310 |
+ |
2+ sfunc funcfile transform |
1311 |
+ |
0 |
1312 |
+ |
2+ nmA nmB A3 .. |
1313 |
+ |
.DE |
1314 |
+ |
Like the spectrum primitive, the wavelength range is specified |
1315 |
+ |
in the first two real arguments, and additional real values are |
1316 |
+ |
set in the evaluation context. |
1317 |
+ |
This function is fed a wavelenth sample |
1318 |
+ |
between nmA and nmB as its only argument, |
1319 |
+ |
and it returns the corresponding spectral intensity. |
1320 |
+ |
.LP |
1321 |
+ |
.UL Specdata |
1322 |
+ |
.PP |
1323 |
+ |
Specdata is like brightdata and colordata, but with more |
1324 |
+ |
than 3 specular samples. |
1325 |
+ |
.DS |
1326 |
+ |
mod specdata id |
1327 |
+ |
3+n+ |
1328 |
+ |
func datafile |
1329 |
+ |
funcfile x1 x2 .. xn transform |
1330 |
+ |
0 |
1331 |
+ |
m A1 A2 .. Am |
1332 |
+ |
.DE |
1333 |
+ |
The data file must have one more dimension than the coordinate |
1334 |
+ |
variable count, as this final dimension corresponds to the covered |
1335 |
+ |
spectrum. |
1336 |
+ |
The starting and ending wavelengths are specified in "datafile" |
1337 |
+ |
as well as the number of spectral samples. |
1338 |
+ |
The function "func" will be called with two parameters, the |
1339 |
+ |
interpolated spectral value for the current coordinate and the |
1340 |
+ |
associated wavelength. |
1341 |
+ |
If the spectrum is broken into 12 components, then 12 calls |
1342 |
+ |
will be made to "func" for the relevant ray evaluation. |
1343 |
+ |
.LP |
1344 |
+ |
.UL Specpict |
1345 |
+ |
.PP |
1346 |
+ |
Specpict is a special case of specdata, where the pattern is |
1347 |
+ |
a hyperspectral image stored in the common-exponent file format. |
1348 |
+ |
The dimensions of the image data are determined by the picture |
1349 |
+ |
just as with the colorpict primitive. |
1350 |
+ |
.DS |
1351 |
+ |
mod specpict id |
1352 |
+ |
5+ |
1353 |
+ |
func specfile |
1354 |
+ |
funcfile u v transform |
1355 |
+ |
0 |
1356 |
+ |
m A1 A2 .. Am |
1357 |
+ |
.DE |
1358 |
+ |
The function "func" is called with the interpolated pixel value |
1359 |
+ |
and the wavelength sample in nanometers, the same as specdata, |
1360 |
+ |
with as many calls made as there are components in "specfile". |
1361 |
|
.NH 3 |
1362 |
|
Mixtures |
1363 |
|
.PP |
1364 |
|
A mixture is a blend of one or more materials or textures and patterns. |
1365 |
+ |
Blended materials should not be light source types or virtual source types. |
1366 |
|
The basic types are given below. |
1367 |
|
.LP |
1368 |
|
.UL Mixfunc |
1384 |
|
Vname is the coefficient defined in funcfile that determines the influence |
1385 |
|
of foreground. |
1386 |
|
The background coefficient is always (1-vname). |
1101 |
– |
Since the references are not resolved until runtime, the last |
1102 |
– |
definitions of the modifier id's will be used. |
1103 |
– |
This can result in modifier loops, which are detected by the |
1104 |
– |
renderer. |
1387 |
|
.LP |
1388 |
|
.UL Mixdata |
1389 |
|
.PP |
1484 |
|
The following variables are particularly important: |
1485 |
|
.DS |
1486 |
|
Dx, Dy, Dz - incident ray direction |
1205 |
– |
Px, Py, Pz - intersection point |
1487 |
|
Nx, Ny, Nz - surface normal at intersection point |
1488 |
+ |
Px, Py, Pz - intersection point |
1489 |
+ |
T - distance from start |
1490 |
+ |
Ts - single ray (shadow) distance |
1491 |
|
Rdot - cosine between ray and normal |
1492 |
|
arg(0) - number of real arguments |
1493 |
|
arg(i) - i'th real argument |
1494 |
|
.DE |
1495 |
+ |
For mesh objects, the local surface coordinates are available: |
1496 |
+ |
.DS |
1497 |
+ |
Lu, Lv - local (u,v) coordinates |
1498 |
+ |
.DE |
1499 |
|
For BRDF types, the following variables are defined as well: |
1500 |
|
.DS |
1501 |
|
NxP, NyP, NzP - perturbed surface normal |
1510 |
|
variables are global, a period (`.') can be given in |
1511 |
|
place of the file name. |
1512 |
|
It is also possible to give an expression instead of a straight |
1513 |
< |
variable name in a scene file, although such expressions should |
1514 |
< |
be kept simple as they cannot contain any white space. |
1227 |
< |
Also, functions (requiring parameters) |
1513 |
> |
variable name in a scene file. |
1514 |
> |
Functions (requiring parameters) |
1515 |
|
must be given as names and not as expressions. |
1516 |
|
.PP |
1517 |
|
Constant expressions are used as an optimization in function |
1675 |
|
Pictures may be displayed directly under X11 using the program |
1676 |
|
.I ximage, |
1677 |
|
or converted a standard image format. |
1678 |
< |
.I Ra_avs |
1679 |
< |
converts to and from AVS image format. |
1393 |
< |
.I Ra_pict |
1394 |
< |
converts to Macintosh 32-bit PICT2 format. |
1678 |
> |
.I Ra_bmp |
1679 |
> |
converts to and from Microsoft Bitmap images. |
1680 |
|
.I Ra_ppm |
1681 |
|
converts to and from Poskanzer Portable Pixmap formats. |
1397 |
– |
.I Ra_pr |
1398 |
– |
converts to and from Sun 8-bit rasterfile format. |
1399 |
– |
.I Ra_pr24 |
1400 |
– |
converts to and from Sun 24-bit rasterfile format. |
1682 |
|
.I Ra_ps |
1683 |
|
converts to PostScript color and greyscale formats. |
1684 |
|
.I Ra_rgbe |
1694 |
|
.NH 1 |
1695 |
|
License |
1696 |
|
.PP |
1697 |
< |
Radiance is a registered copyright of The Regents of the University of |
1698 |
< |
California ("The Regents"). The Regents grant to you a nonexclusive, |
1699 |
< |
nontransferable license ("License") to use Radiance source code without fee. |
1700 |
< |
You may not sell or distribute Radiance to others without the prior express |
1701 |
< |
written permission of The Regents. |
1702 |
< |
You may compile and use this software on any machines to which you have |
1703 |
< |
personal access, and may share its use with others who have access to the |
1704 |
< |
same machines. |
1705 |
< |
.PP |
1706 |
< |
NEITHER THE UNITED STATES NOR THE UNITED STATES DEPARTMENT OF ENERGY, NOR ANY |
1707 |
< |
OF THEIR EMPLOYEES, MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY |
1708 |
< |
LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR |
1709 |
< |
USEFULNESS OF ANY INFORMATION, APPARATUS, PRODUCT, OR PROCESS DISCLOSED, OR |
1710 |
< |
REPRESENTS THAT ITS USE WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS. |
1711 |
< |
By downloading, using or copying this software, you agree to abide by the |
1712 |
< |
intellectual property laws and all other applicable laws of the United |
1713 |
< |
States, and by the terms of this License Agreement. Ownership of the software |
1714 |
< |
shall remain solely in The Regents. |
1715 |
< |
The Regents shall have the right to terminate this License immediately by |
1716 |
< |
written notice upon your breach of, or noncompliance with, any of its terms. |
1717 |
< |
You shall be liable for any infringement or damages resulting from your |
1718 |
< |
failure to abide by the terms of this License Agreement. |
1719 |
< |
.PP |
1720 |
< |
NOTICE: The Government is granted for itself and others acting on its behalf |
1721 |
< |
a paid-up, nonexclusive irrevocable worldwide license in this data to |
1722 |
< |
reproduce, prepare derivative works, and perform publicly and display |
1723 |
< |
publicly. Beginning five (5) years after permission to assert copyright is |
1724 |
< |
granted, subject to two possible five year renewals, the Government is |
1725 |
< |
granted for itself and others acting on its behalf a paid-up, non-exclusive, |
1726 |
< |
irrevocable worldwide license in this data to reproduce, prepare derivative |
1727 |
< |
works, distribute copies to the public, perform publicly and display |
1728 |
< |
publicly, and to permit others to do so. |
1697 |
> |
.DS |
1698 |
> |
The Radiance Software License, Version 1.0 |
1699 |
> |
|
1700 |
> |
Copyright (c) 1990 - 2008 The Regents of the University of California, |
1701 |
> |
through Lawrence Berkeley National Laboratory. All rights reserved. |
1702 |
> |
|
1703 |
> |
Redistribution and use in source and binary forms, with or without |
1704 |
> |
modification, are permitted provided that the following conditions |
1705 |
> |
are met: |
1706 |
> |
|
1707 |
> |
1. Redistributions of source code must retain the above copyright |
1708 |
> |
notice, this list of conditions and the following disclaimer. |
1709 |
> |
|
1710 |
> |
2. Redistributions in binary form must reproduce the above copyright |
1711 |
> |
notice, this list of conditions and the following disclaimer in |
1712 |
> |
the documentation and/or other materials provided with the |
1713 |
> |
distribution. |
1714 |
> |
|
1715 |
> |
3. The end-user documentation included with the redistribution, |
1716 |
> |
if any, must include the following acknowledgment: |
1717 |
> |
"This product includes Radiance software |
1718 |
> |
(http://radsite.lbl.gov/) |
1719 |
> |
developed by the Lawrence Berkeley National Laboratory |
1720 |
> |
(http://www.lbl.gov/)." |
1721 |
> |
Alternately, this acknowledgment may appear in the software itself, |
1722 |
> |
if and wherever such third-party acknowledgments normally appear. |
1723 |
> |
|
1724 |
> |
4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
1725 |
> |
and "The Regents of the University of California" must |
1726 |
> |
not be used to endorse or promote products derived from this |
1727 |
> |
software without prior written permission. For written |
1728 |
> |
permission, please contact [email protected]. |
1729 |
> |
|
1730 |
> |
5. Products derived from this software may not be called "Radiance", |
1731 |
> |
nor may "Radiance" appear in their name, without prior written |
1732 |
> |
permission of Lawrence Berkeley National Laboratory. |
1733 |
> |
|
1734 |
> |
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
1735 |
> |
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
1736 |
> |
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
1737 |
> |
DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR |
1738 |
> |
ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
1739 |
> |
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
1740 |
> |
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
1741 |
> |
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
1742 |
> |
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
1743 |
> |
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
1744 |
> |
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
1745 |
> |
SUCH DAMAGE. |
1746 |
> |
.DE |
1747 |
|
.NH 1 |
1748 |
|
Acknowledgements |
1749 |
|
.PP |
1759 |
|
in Lausanne, Switzerland. |
1760 |
|
.NH 1 |
1761 |
|
References |
1762 |
+ |
.LP |
1763 |
+ |
Ward, Gregory J., Bruno Bueno, David Geisler-Moroder, |
1764 |
+ |
Lars O. Grobe, Jacob C. Jonsson, Eleanor |
1765 |
+ |
S. Lee, Taoning Wang, Helen Rose Wilson, |
1766 |
+ |
``Daylight Simulation Workflows Incorporating |
1767 |
+ |
Measured Bidirectional Scattering Distribution Functions,'' |
1768 |
+ |
.I "Energy & Buildings", |
1769 |
+ |
Vol. 259, No. 111890, 2022. |
1770 |
+ |
.LP |
1771 |
+ |
Wang, Taoning, Gregory Ward, Eleanor Lee, |
1772 |
+ |
``Efficient modeling of optically-complex, non-coplanar |
1773 |
+ |
exterior shading: Validation of matrix algebraic methods,'' |
1774 |
+ |
.I "Energy & Buildings", |
1775 |
+ |
vol. 174, pp. 464-83, Sept. 2018. |
1776 |
+ |
.LP |
1777 |
+ |
Lee, Eleanor S., David Geisler-Moroder, Gregory Ward, |
1778 |
+ |
``Modeling the direct sun component in buildings using matrix |
1779 |
+ |
algebraic approaches: Methods and validation,'' |
1780 |
+ |
.I Solar Energy, |
1781 |
+ |
vol. 160, 15 January 2018, pp 380-395. |
1782 |
+ |
.LP |
1783 |
+ |
Ward, G., M. Kurt & N. Bonneel, |
1784 |
+ |
``Reducing Anisotropic BSDF Measurement to Common Practice,'' |
1785 |
+ |
.I Workshop on Material Appearance Modeling, |
1786 |
+ |
2014. |
1787 |
+ |
.LP |
1788 |
+ |
McNeil, A., C.J. Jonsson, D. Appelfeld, G. Ward, E.S. Lee, |
1789 |
+ |
``A validation of a ray-tracing tool used to generate |
1790 |
+ |
bi-directional scattering distribution functions for |
1791 |
+ |
complex fenestration systems,'' |
1792 |
+ |
.I "Solar Energy", |
1793 |
+ |
98, 404-14, November 2013. |
1794 |
+ |
.LP |
1795 |
+ |
Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson, |
1796 |
+ |
``Simulating the Daylight Performance of Complex Fenestration Systems |
1797 |
+ |
Using Bidirectional Scattering Distribution Functions within Radiance,'' |
1798 |
+ |
.I "Leukos", |
1799 |
+ |
7(4), |
1800 |
+ |
April 2011. |
1801 |
+ |
.LP |
1802 |
+ |
Cater, K., A. Chalmers, G. Ward, |
1803 |
+ |
``Detail to Attention: Exploiting Visual Tasks for Selective Rendering,'' |
1804 |
+ |
.I "Eurograhics Symposium on Rendering", |
1805 |
+ |
June 2003. |
1806 |
+ |
.LP |
1807 |
+ |
Ward, G., Elena Eydelberg-Vileshin, |
1808 |
+ |
``Picture Perfect RGB Rendering Using Spectral Prefiltering and |
1809 |
+ |
Sharp Color Primaries,'' |
1810 |
+ |
13th Eurographics Workshop on Rendering, P. Debevec and |
1811 |
+ |
S. Gibson (Editors), June 2002. |
1812 |
+ |
.LP |
1813 |
+ |
Ward, G. and M. Simmons, |
1814 |
+ |
``The Holodeck Ray Cache: An Interactive Rendering System for Global |
1815 |
+ |
Illumination in Nondiffuse Environments,'' |
1816 |
+ |
.I "ACM Transactions on Graphics," |
1817 |
+ |
18(4):361-98, October 1999. |
1818 |
+ |
.LP |
1819 |
+ |
Larson, G.W., H. Rushmeier, C. Piatko, |
1820 |
+ |
``A Visibility Matching Tone Reproduction Operator for High Dynamic |
1821 |
+ |
Range Scenes,'' |
1822 |
+ |
.I "IEEE Transactions on Visualization and Computer Graphics", |
1823 |
+ |
3(4), 291-306, December 1997. |
1824 |
+ |
.LP |
1825 |
+ |
Ward, G., |
1826 |
+ |
``Making Global Illumination User Friendly,'' |
1827 |
+ |
.I "Sixth Eurographics Workshop on Rendering", |
1828 |
+ |
proceedings to be published by Springer-Verlag, |
1829 |
+ |
Dublin, Ireland, June 1995. |
1830 |
+ |
.LP |
1831 |
+ |
Rushmeier, H., G. Ward, C. Piatko, P. Sanders, B. Rust, |
1832 |
+ |
``Comparing Real and Synthetic Images: Some Ideas about Metrics,'' |
1833 |
+ |
.I "Sixth Eurographics Workshop on Rendering", |
1834 |
+ |
proceedings to be published by Springer-Verlag, |
1835 |
+ |
Dublin, Ireland, June 1995. |
1836 |
|
.LP |
1837 |
|
Ward, G., |
1838 |
|
``The Radiance Lighting Simulation and Rendering System,'' |