| 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 sBSDF |
| 951 |
+ |
.PP |
| 952 |
+ |
The sBSDF 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 sBSDF is assumed to have some specular through component, which |
| 956 |
+ |
is treated specially during the direct calculation and when viewing the |
| 957 |
+ |
material. |
| 958 |
+ |
Based on the BSDF data, the coefficient of specular transmission is |
| 959 |
+ |
determined and used for modifying unscattered shadow and view rays. |
| 960 |
+ |
.DS |
| 961 |
+ |
mod sBSDF id |
| 962 |
+ |
5+ BSDFfile ux uy uz funcfile transform |
| 963 |
+ |
0 |
| 964 |
+ |
0|3|6|9 |
| 965 |
+ |
rfdif gfdif bfdif |
| 966 |
+ |
rbdif gbdif bbdif |
| 967 |
+ |
rtdif gtdif btdif |
| 968 |
+ |
.DE |
| 969 |
+ |
.LP |
| 970 |
+ |
If a material has no specular transmitted component, it is much better |
| 971 |
+ |
to use the BSDF type with a zero thickness than to use sBSDF. |
| 972 |
+ |
.LP |
| 973 |
|
.UL Antimatter |
| 974 |
|
.PP |
| 975 |
|
Antimatter is a material that can "subtract" volumes from other volumes. |
