| 1 |
< |
.\" RCSid "$Id" |
| 1 |
> |
.\" RCSid "$Id$" |
| 2 |
|
.\" Print using the -ms macro package |
| 3 |
< |
.DA 10/26/2011 |
| 3 |
> |
.DA 10/08/2018 |
| 4 |
|
.LP |
| 5 |
< |
.tl """Copyright \(co 2011 Regents, University of California |
| 5 |
> |
.tl """Copyright \(co 2018 Regents, University of California |
| 6 |
|
.sp 2 |
| 7 |
|
.TL |
| 8 |
|
The |
| 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 |
+ |
.DS |
| 634 |
+ |
mod ashik2 id |
| 635 |
+ |
4+ ux uy uz funcfile transform |
| 636 |
+ |
0 |
| 637 |
+ |
8 dred dgrn dblu sred sgrn sblu u-power v-power |
| 638 |
+ |
.DE |
| 639 |
+ |
.LP |
| 640 |
|
.UL Dielectric |
| 641 |
|
.PP |
| 642 |
|
A dielectric material is transparent, and it refracts light |
| 947 |
|
Unlike other data-driven material types, the BSDF type is fully |
| 948 |
|
supported and all parts of the distribution are properly sampled. |
| 949 |
|
.LP |
| 950 |
+ |
.UL aBSDF |
| 951 |
+ |
.PP |
| 952 |
+ |
The aBSDF material is identical to the BSDF type with two important |
| 953 |
+ |
differences. |
| 954 |
+ |
First, proxy geometry is not supported, so there is no thickness parameter. |
| 955 |
+ |
Second, an aBSDF is assumed to have some specular through component |
| 956 |
+ |
(the 'a' stands for "aperture"), which |
| 957 |
+ |
is treated specially during the direct calculation and when viewing the |
| 958 |
+ |
material. |
| 959 |
+ |
Based on the BSDF data, the coefficient of specular transmission is |
| 960 |
+ |
determined and used for modifying unscattered shadow and view rays. |
| 961 |
+ |
.DS |
| 962 |
+ |
mod aBSDF id |
| 963 |
+ |
5+ BSDFfile ux uy uz funcfile transform |
| 964 |
+ |
0 |
| 965 |
+ |
0|3|6|9 |
| 966 |
+ |
rfdif gfdif bfdif |
| 967 |
+ |
rbdif gbdif bbdif |
| 968 |
+ |
rtdif gtdif btdif |
| 969 |
+ |
.DE |
| 970 |
+ |
.LP |
| 971 |
+ |
If a material has no specular transmitted component, it is much better |
| 972 |
+ |
to use the BSDF type with a zero thickness than to use aBSDF. |
| 973 |
+ |
.LP |
| 974 |
|
.UL Antimatter |
| 975 |
|
.PP |
| 976 |
|
Antimatter is a material that can "subtract" volumes from other volumes. |
| 985 |
|
The first modifier will also be used to shade the area leaving the |
| 986 |
|
antimatter volume and entering the regular volume. |
| 987 |
|
If mod1 is void, the antimatter volume is completely invisible. |
| 988 |
< |
Antimatter does not work properly with the material type "trans", |
| 989 |
< |
and multiple antimatter surfaces should be disjoint. |
| 988 |
> |
If shading is desired at antimatter surfaces, it is important |
| 989 |
> |
that the related volumes are closed with outward-facing normals. |
| 990 |
> |
Antimatter surfaces should not intersect with other antimatter boundaries, |
| 991 |
> |
and it is unwise to use the same modifier in nested antimatter volumes. |
| 992 |
|
The viewpoint must be outside all volumes concerned for a correct |
| 993 |
|
rendering. |
| 994 |
|
.NH 3 |
| 1196 |
|
Mixtures |
| 1197 |
|
.PP |
| 1198 |
|
A mixture is a blend of one or more materials or textures and patterns. |
| 1199 |
+ |
Blended materials should not be light source types or virtual source types. |
| 1200 |
|
The basic types are given below. |
| 1201 |
|
.LP |
| 1202 |
|
.UL Mixfunc |
| 1593 |
|
in Lausanne, Switzerland. |
| 1594 |
|
.NH 1 |
| 1595 |
|
References |
| 1596 |
+ |
.LP |
| 1597 |
+ |
Wang, Taoning, Gregory Ward, Eleanor Lee, |
| 1598 |
+ |
``Efficient modeling of optically-complex, non-coplanar |
| 1599 |
+ |
exterior shading: Validation of matrix algebraic methods,'' |
| 1600 |
+ |
.I "Energy & Buildings", |
| 1601 |
+ |
vol. 174, pp. 464-83, Sept. 2018. |
| 1602 |
+ |
.LP |
| 1603 |
+ |
Lee, Eleanor S., David Geisler-Moroder, Gregory Ward, |
| 1604 |
+ |
``Modeling the direct sun component in buildings using matrix |
| 1605 |
+ |
algebraic approaches: Methods and validation,'' |
| 1606 |
+ |
.I Solar Energy, |
| 1607 |
+ |
vol. 160, 15 January 2018, pp 380-395. |
| 1608 |
+ |
.LP |
| 1609 |
+ |
Ward, G., M. Kurt & N. Bonneel, |
| 1610 |
+ |
``Reducing Anisotropic BSDF Measurement to Common Practice,'' |
| 1611 |
+ |
.I Workshop on Material Appearance Modeling, |
| 1612 |
+ |
2014. |
| 1613 |
+ |
.LP |
| 1614 |
+ |
McNeil, A., C.J. Jonsson, D. Appelfeld, G. Ward, E.S. Lee, |
| 1615 |
+ |
``A validation of a ray-tracing tool used to generate |
| 1616 |
+ |
bi-directional scattering distribution functions for |
| 1617 |
+ |
complex fenestration systems,'' |
| 1618 |
+ |
.I "Solar Energy", |
| 1619 |
+ |
98, 404-14, November 2013. |
| 1620 |
|
.LP |
| 1621 |
|
Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson, |
| 1622 |
|
``Simulating the Daylight Performance of Complex Fenestration Systems |
