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Comparing ray/doc/ray.1 (file contents):
Revision 1.46 by greg, Wed Dec 13 23:26:16 2023 UTC vs.
Revision 1.49 by greg, Fri May 30 16:35:52 2025 UTC

# Line 1 | Line 1
1   .\" RCSid "$Id$"
2   .\" Print using the -ms macro package
3 < .DA 11/13/2023
3 > .DA 12/09/2024
4   .LP
5 < .tl """Copyright \(co 2023 Regents, University of California
5 > .tl """Copyright \(co 2024 Regents, University of California
6   .sp 2
7   .TL
8   The
# Line 422 | Line 422 | mod mirror id
422   0
423   3 red green blue
424   .DE
425 + While alternate materials that are reflective will appear as normal,
426 + indirect rays will use the mirror's reflectance rather than the
427 + alternate type.
428 + Transmitting materials are an exception, where both transmission and
429 + reflection will use the alternate type for all rays not specifically
430 + targeting virtual light sources.
431 + In this case, it is important that any reflections be purely specular
432 + (mirror-like) and equal to the mirror's reflectivity
433 + to maintain a valid result.
434 + A pure diffuse reflection may be added if desired.
435 + .PP
436 + The mirror material type reflects light sources only from the front side
437 + of a surface, regardless of any alternate material.
438 + If virtual source generation is desired on both sides, two coincident
439 + surfaces with opposite normal orientations may be employed to achieve
440 + this effect.
441 + The reflectance and alternate material type may be
442 + different for the overlapped surfaces,
443 + and the two sides will behave accordingly.
444   .LP
445   .UL Prism1
446   .PP
# Line 638 | Line 657 | mod ashik2 id
657   0
658   8 dred dgrn dblu sred sgrn sblu u-power v-power
659   .DE
660 + .LP
661 + .UL WGMDfunc
662 + .PP
663 + WGMDfunc is a more programmable version of trans2,
664 + with separate modifier paths and variables to control each component.
665 + (WGMD stands for Ward-Geisler-Moroder-Duer, which is the basis for
666 + this empirical model, similar to the previous ones beside Ashik2.)\0
667 + The specification of this material is given below.
668 + .DS
669 + mod WGMDfunc id
670 + 13+ rs_mod  rs  rs_urough rs_vrough
671 +    ts_mod  ts  ts_urough ts_vrough
672 +    td_mod
673 +    ux uy uz  funcfile  transform
674 + 0
675 + 9+  rfdif gfdif bfdif
676 +    rbdif gbdif bbdif
677 +    rtdif gtdif btdif
678 +    A10 ..
679 + .DE
680 + The sum of specular reflectance (
681 + .I rs
682 + ), specular transmittance (
683 + .I ts
684 + ), diffuse reflectance (
685 + .I "rfdif gfdif bfdif"
686 + for front and
687 + .I "rbdif gbdif bbdif"
688 + for back)
689 + and diffuse transmittance (
690 + .I "rtdif gtdif btdif"
691 + ) should be less than 1 for each
692 + channel.
693 + .PP
694 + Unique to this material, separate modifier channels are
695 + provided for each component.
696 + The main modifier is used on the diffuse reflectance, both
697 + front and back.
698 + The
699 + .I rs_mod
700 + modifier is used for specular reflectance.
701 + If "void" is given for
702 + .I rs_mod,
703 + then the specular reflection color will be white.
704 + The special "inherit" keyword may also be given, in which case
705 + specular reflectance will share the main modifier.
706 + This behavior is replicated for the specular transmittance modifier
707 + .I ts_mod,
708 + which has its own independent roughness expressions.
709 + Finally, the diffuse transmittance modifier is given as
710 + .I td_mod,
711 + which may also be "void" or "inherit".
712 + Note that any spectra or color for specular components must be
713 + carried by the named modifier(s).
714 + .PP
715 + The main advantage to this material over BRTDfunc and
716 + other programmable types described below is that the specular sampling is
717 + well-defined, so that all components are fully computed.
718   .LP
719   .UL Dielectric
720   .PP

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