| 898 |
|
a parallel BSDF surface may be |
| 899 |
|
placed slightly less than the given thickness away from the front surface |
| 900 |
|
to enclose the complex geometry on both sides. |
| 901 |
+ |
The sign of the thickness is important, as it indicates whether the |
| 902 |
+ |
proxied geometry is behind the. |
| 903 |
+ |
.I BSDF |
| 904 |
+ |
surface (when thickness is positive) |
| 905 |
+ |
or in front (when thickness is negative). |
| 906 |
|
.LP |
| 907 |
|
The second string argument is the name of the BSDF file, which is |
| 908 |
|
found in the usual auxiliary locations. |
