1063 |
|
Real arguments to this material may define additional |
1064 |
|
diffuse components that augment the BSDF data. |
1065 |
|
String arguments are used to define thickness for proxied |
1066 |
< |
surfaces and the "up" orientation for the material. |
1066 |
> |
surfaces and the "up" orientation for the material. |
1067 |
|
|
1068 |
|
<pre> |
1069 |
|
mod BSDF id |
1076 |
|
</pre> |
1077 |
|
|
1078 |
|
<p> |
1079 |
< |
The first string argument is a "thickness" parameter that may be used |
1079 |
> |
The first string argument is a "thickness" parameter that may be used |
1080 |
|
to hide detail geometry being proxied by an aggregate BSDF material. |
1081 |
|
If a view or shadow ray hits a BSDF proxy with non-zero thickness, |
1082 |
|
it will pass directly through as if the surface were not there. |
1092 |
|
a parallel BSDF surface may be |
1093 |
|
placed slightly less than the given thickness away from the front surface |
1094 |
|
to enclose the complex geometry on both sides. |
1095 |
+ |
The sign of the thickness is important, as it indicates |
1096 |
+ |
whether the proxied geometry is behind the <em>BSDF</em> |
1097 |
+ |
surface (when thickness is positive) or in front (when |
1098 |
+ |
thickness is negative). |
1099 |
|
<p> |
1100 |
< |
The second string argument is the name of the BSDF file, which is |
1101 |
< |
found in the usual auxiliary locations. |
1102 |
< |
The following three string parameters name variables for an "up" vector, |
1103 |
< |
which together with the surface normal, define the |
1104 |
< |
local coordinate system that orients the BSDF. |
1105 |
< |
These variables, along with the thickness, are defined in a function |
1106 |
< |
file given as the next string argument. |
1107 |
< |
An optional transform is used to scale the thickness and reorient the up vector. |
1100 |
> |
The second string argument is the name of the BSDF file, |
1101 |
> |
which is found in the usual auxiliary locations. The |
1102 |
> |
following three string parameters name variables for an |
1103 |
> |
"up" vector, which together with the surface |
1104 |
> |
normal, define the local coordinate system that orients the |
1105 |
> |
BSDF. These variables, along with the thickness, are defined |
1106 |
> |
in a function file given as the next string argument. An |
1107 |
> |
optional transform is used to scale the thickness and |
1108 |
> |
reorient the up vector. |
1109 |
|
<p> |
1110 |
< |
If no real arguments are given, the BSDF is used by itself to determine |
1111 |
< |
reflection and transmission. |
1112 |
< |
If there are at least 3 real arguments, the first triplet is an |
1113 |
< |
additional diffuse reflectance for the front side. |
1114 |
< |
At least 6 real arguments adds diffuse reflectance to the rear side of the surface. |
1115 |
< |
If there are 9 real arguments, the final triplet will be taken as an additional |
1116 |
< |
diffuse transmittance. |
1117 |
< |
All diffuse components as well as the non-diffuse transmission are |
1118 |
< |
modified by patterns applied to this material. |
1119 |
< |
The non-diffuse reflection from either side are unaffected. |
1120 |
< |
Textures perturb the effective surface normal in the usual way. |
1110 |
> |
If no real arguments are given, the BSDF is used by itself |
1111 |
> |
to determine reflection and transmission. If there are at |
1112 |
> |
least 3 real arguments, the first triplet is an additional |
1113 |
> |
diffuse reflectance for the front side. At least 6 real |
1114 |
> |
arguments adds diffuse reflectance to the rear side of the |
1115 |
> |
surface. If there are 9 real arguments, the final triplet |
1116 |
> |
will be taken as an additional diffuse transmittance. All |
1117 |
> |
diffuse components as well as the non-diffuse transmission |
1118 |
> |
are modified by patterns applied to this material. The |
1119 |
> |
non-diffuse reflection from either side are unaffected. |
1120 |
> |
Textures perturb the effective surface normal in the usual |
1121 |
> |
way. |
1122 |
|
<p> |
1123 |
< |
The surface normal of this type is not altered to face the incoming ray, |
1124 |
< |
so the front and back BSDF reflections may differ. |
1125 |
< |
(Transmission is identical front-to-back by physical law.)\0 |
1126 |
< |
If back visibility is turned off during rendering and there is no |
1127 |
< |
transmission or back-side reflection, only then the surface will be |
1128 |
< |
invisible from behind. |
1129 |
< |
Unlike other data-driven material types, the BSDF type is fully |
1130 |
< |
supported and all parts of the distribution are properly sampled. |
1123 |
> |
The surface normal of this type is not altered to face the |
1124 |
> |
incoming ray, so the front and back BSDF reflections may |
1125 |
> |
differ. (Transmission is identical front-to-back by physical |
1126 |
> |
law.) If back visibility is turned off during rendering and |
1127 |
> |
there is no transmission or back-side reflection, only then |
1128 |
> |
the surface will be invisible from behind. Unlike other |
1129 |
> |
data-driven material types, the BSDF type is fully supported |
1130 |
> |
and all parts of the distribution are properly sampled. |
1131 |
|
<p> |
1132 |
|
|
1133 |
|
<dt> |