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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 1.48 by greg, Thu May 29 16:42:28 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 + Therefore, transmitting alternate types should only have pure specular
432 + reflection if they reflect at all, to maintain a valid calculation.
433 + .PP
434 + The mirror material type reflects light sources only from the front side
435 + of a surface, regardless of any alternate material.
436 + If virtual source generation is desired on both sides, two coincident
437 + surfaces with opposite normal orientations may be employed to achieve
438 + this effect.
439 + The reflectance and alternate material type may be
440 + different for the overlapped surfaces,
441 + and the two sides will behave accordingly.
442   .LP
443   .UL Prism1
444   .PP
# Line 638 | Line 655 | mod ashik2 id
655   0
656   8 dred dgrn dblu sred sgrn sblu u-power v-power
657   .DE
658 + .LP
659 + .UL WGMDfunc
660 + .PP
661 + WGMDfunc is a more programmable version of trans2,
662 + with separate modifier paths and variables to control each component.
663 + (WGMD stands for Ward-Geisler-Moroder-Duer, which is the basis for
664 + this empirical model, similar to the previous ones beside Ashik2.)\0
665 + The specification of this material is given below.
666 + .DS
667 + mod WGMDfunc id
668 + 13+ rs_mod  rs  rs_urough rs_vrough
669 +    ts_mod  ts  ts_urough ts_vrough
670 +    td_mod
671 +    ux uy uz  funcfile  transform
672 + 0
673 + 9+  rfdif gfdif bfdif
674 +    rbdif gbdif bbdif
675 +    rtdif gtdif btdif
676 +    A10 ..
677 + .DE
678 + The sum of specular reflectance (
679 + .I rs
680 + ), specular transmittance (
681 + .I ts
682 + ), diffuse reflectance (
683 + .I "rfdif gfdif bfdif"
684 + for front and
685 + .I "rbdif gbdif bbdif"
686 + for back)
687 + and diffuse transmittance (
688 + .I "rtdif gtdif btdif"
689 + ) should be less than 1 for each
690 + channel.
691 + .PP
692 + Unique to this material, separate modifier channels are
693 + provided for each component.
694 + The main modifier is used on the diffuse reflectance, both
695 + front and back.
696 + The
697 + .I rs_mod
698 + modifier is used for specular reflectance.
699 + If "void" is given for
700 + .I rs_mod,
701 + then the specular reflection color will be white.
702 + The special "inherit" keyword may also be given, in which case
703 + specular reflectance will share the main modifier.
704 + This behavior is replicated for the specular transmittance modifier
705 + .I ts_mod,
706 + which has its own independent roughness expressions.
707 + Finally, the diffuse transmittance modifier is given as
708 + .I td_mod,
709 + which may also be "void" or "inherit".
710 + Note that any spectra or color for specular components must be
711 + carried by the named modifier(s).
712 + .PP
713 + The main advantage to this material over BRTDfunc and
714 + other programmable types described below is that the specular sampling is
715 + well-defined, so that all components are fully computed.
716   .LP
717   .UL Dielectric
718   .PP

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