| 147 |
|
Bidirectional emission; photons are emitted from both sides of the port. |
| 148 |
|
.RE |
| 149 |
|
.IP |
| 150 |
< |
Situations that call for a reversed photon port include, for |
| 151 |
< |
example, using fenestrations as ports that were (for whatever |
| 152 |
< |
reason) defined with outward facing normals, or using a \fBmist\fR |
| 150 |
> |
Some typical situations that call for a reversed photon port include, for |
| 151 |
> |
example: |
| 152 |
> |
.RS |
| 153 |
> |
.IP (a) |
| 154 |
> |
Using fenestrations as ports that were (for whatever |
| 155 |
> |
reason) defined with outward facing normals, |
| 156 |
> |
.IP (b) |
| 157 |
> |
Using a \fBmist\fR |
| 158 |
|
primitive as a port, since this requires outward facing normals in order to |
| 159 |
< |
register the photons as having entered the volume. |
| 159 |
> |
register the photons as having entered the volume, |
| 160 |
> |
.IP (c) |
| 161 |
> |
Reorienting a port associated with a \fBbsdf\fR modifier, since inverting |
| 162 |
> |
its normal would also reorient the BSDF and alter its behaviour. |
| 163 |
> |
.RE |
| 164 |
> |
.IP |
| 165 |
> |
Other oddball scenarios are conceivable. If in doubt, specify a |
| 166 |
> |
bidirectional port orientation for a slight performance penalty, |
| 167 |
> |
as photon emission is attempted from both sides. For well-defined |
| 168 |
> |
port geometry with inward-facing normals, just use the default; |
| 169 |
> |
doan' mess with da normalz. |
| 170 |
> |
.IP |
| 171 |
> |
Photon port geometry is discretised according to the |
| 172 |
> |
\fB\-dp\fR and \fB\-ds\fR options. These parameters aid in resolving |
| 173 |
> |
spatially and directionally varying illuminance received by the port |
| 174 |
> |
from distant light sources, e.g due to partial occlusion |
| 175 |
> |
or when using climate-based sky models. |
| 176 |
|
|
| 177 |
|
.IP "\fB\-apO \fImodfile\fR" |
| 178 |
|
Read photon port modifiers from the file \fImodfile\fR as a more convenient |
| 243 |
|
are unconditionally absorbed and discarded. |
| 244 |
|
|
| 245 |
|
.IP "\fB\-dp \fIsampleres\fR" |
| 246 |
< |
Resolution for sampling the spatial emission distribution of a modified |
| 247 |
< |
light source (e.g. via \fIbrightfunc\fR), in samples per steradian. This |
| 248 |
< |
is required for numerically integrating the flux emitted by the light |
| 249 |
< |
source and for constructing a probability density function for photon |
| 250 |
< |
emission. The accuracy of photon emission from modified sources |
| 251 |
< |
therefore depends on this parameter. This parameter may need increasing |
| 246 |
> |
Angular resolution for sampling the spatial emission distribution of a |
| 247 |
> |
modified light source or photon port (e.g. via \fIbrightfunc\fR), in samples |
| 248 |
> |
per steradian. |
| 249 |
> |
This is required to numerically integrate the flux emitted by the light |
| 250 |
> |
source and construct a probability density function for photon emission. |
| 251 |
> |
The accuracy of photon emission from a modified source or port |
| 252 |
> |
therefore depends on this parameter. The resolution may need to be increased |
| 253 |
|
with complex emission distributions in combination with caustics. |
| 254 |
|
|
| 255 |
|
.IP "\fB\-ds \fIpartsize\fR" |
| 256 |
< |
Light source partition size ratio; a light source object is spatially |
| 257 |
< |
partitioned to distribute the photon emission over its surface. This |
| 258 |
< |
parameter specifies the ratio of the size (per dimension) of each |
| 259 |
< |
partition to the scene cube, and may need increasing for modified light |
| 260 |
< |
sources (e.g. via \fIbrightfunc\fR) with high spatial variation. |
| 256 |
> |
Light source partition size ratio; a local light source object (or photon |
| 257 |
> |
port in case of a distant source) is spatially partitioned to distribute the |
| 258 |
> |
photon emission over its surface. This parameter specifies the ratio of the |
| 259 |
> |
size (per dimension) of each partition to the scene cube, and may need |
| 260 |
> |
to be increased for modified light sources (e.g. via \fIbrightfunc\fR) with |
| 261 |
> |
high spatial variance, or for partially occluded photon ports. |
| 262 |
|
|
| 263 |
|
.IP "\fB\-e \fIfile\fR" |
| 264 |
|
Redirect diagnostics and progress reports to \fIfile\fR instead of the |
| 306 |
|
|
| 307 |
|
.IP "\fB\-n \fInproc\fR" |
| 308 |
|
Use \fInproc\fR processes for parallel photon distribution. There is no |
| 309 |
< |
benefit in specifying more than the number of physical CPU cores available. |
| 310 |
< |
This option is currently not available on Windows. |
| 309 |
> |
benefit in specifying more than the number of physical CPU cores available |
| 310 |
> |
(so doan' even try). This option is currently not available on Windows -- |
| 311 |
> |
so there, tuff luck. |
| 312 |
|
|
| 313 |
|
.IP "\fB\-t \fIinterval\fR" |
| 314 |
|
Output a progress report every \fIinterval\fR seconds. This includes |
| 413 |
|
|
| 414 |
|
.RS |
| 415 |
|
\fIFraunhofer Institute for Solar Energy Systems\fR funded by |
| 416 |
< |
the German Research Foundation (\fIDFG LU204/10-2\fR, "Fassadenintegrierte |
| 416 |
> |
the German Research Foundation (\fIDFG LU-204/10-2\fR, "Fassadenintegrierte |
| 417 |
|
Regelsysteme (FARESYS)"), |
| 418 |
|
|
| 419 |
|
\fILucerne University of Applied Sciences and Arts\fR funded by |
