| 188 |
|
.I \-dv |
| 189 |
|
option (below) may be used to override this. |
| 190 |
|
This option is especially useful in |
| 191 |
< |
conjunction with ximage(1) for computing illuminance at scene points. |
| 191 |
> |
conjunction with ximage(1) for computing irradiance at scene points. |
| 192 |
|
.TP |
| 193 |
|
.BR \-u |
| 194 |
|
Boolean switch to control uncorrelated random sampling. |
| 317 |
|
specification will be calculated. |
| 318 |
|
.TP |
| 319 |
|
.BI -dr \ N |
| 320 |
< |
Set the number of relays for secondary sources to |
| 320 |
> |
Set the number of relays for virtual sources to |
| 321 |
|
.I N. |
| 322 |
< |
A value of 0 means that secondary sources will be ignored. |
| 322 |
> |
A value of 0 means that virtual sources will be ignored. |
| 323 |
|
A value of 1 means that sources will be made into first generation |
| 324 |
< |
secondary sources; a value of 2 means that first generation |
| 325 |
< |
secondary sources will also be made into second generation secondary |
| 324 |
> |
virtual sources; a value of 2 means that first generation |
| 325 |
> |
virtual sources will also be made into second generation virtual |
| 326 |
|
sources, and so on. |
| 327 |
|
.TP |
| 328 |
|
.BI -dp \ D |
| 329 |
< |
Set the secondary source presampling density to D. |
| 329 |
> |
Set the virtual source presampling density to D. |
| 330 |
|
This is the number of samples per steradian |
| 331 |
|
that will be used to determine ahead of time whether or not |
| 332 |
|
it is worth following shadow rays through all the reflections and/or |
| 333 |
< |
transmissions associated with a secondary source path. |
| 334 |
< |
A value of 0 means that the full secondary source path will always |
| 333 |
> |
transmissions associated with a virtual source path. |
| 334 |
> |
A value of 0 means that the full virtual source path will always |
| 335 |
|
be tested for shadows if it is tested at all. |
| 336 |
|
.TP |
| 337 |
|
.BR \-dv |
| 444 |
|
Set the ambient accuracy to |
| 445 |
|
.I acc. |
| 446 |
|
This value will approximately equal the error |
| 447 |
< |
from indirect illuminance interpolation. |
| 447 |
> |
from indirect irradiance interpolation. |
| 448 |
|
A value of zero implies no interpolation. |
| 449 |
|
.TP |
| 450 |
|
.BI -ad \ N |
| 451 |
|
Set the number of ambient divisions to |
| 452 |
|
.I N. |
| 453 |
|
The error in the Monte Carlo calculation of indirect |
| 454 |
< |
illuminance will be inversely proportional to the square |
| 454 |
> |
irradiance will be inversely proportional to the square |
| 455 |
|
root of this number. |
| 456 |
|
A value of zero implies no indirect calculation. |
| 457 |
|
.TP |
| 464 |
|
.BI -af \ fname |
| 465 |
|
Set the ambient file to |
| 466 |
|
.I fname. |
| 467 |
< |
This is where indirect illuminance will be stored and retrieved. |
| 468 |
< |
Normally, indirect illuminance values are kept in memory and |
| 467 |
> |
This is where indirect irradiance will be stored and retrieved. |
| 468 |
> |
Normally, indirect irradiance values are kept in memory and |
| 469 |
|
lost when the program finishes or dies. |
| 470 |
< |
By using a file, different invocations can share illuminance |
| 470 |
> |
By using a file, different invocations can share irradiance |
| 471 |
|
values, saving time in the computation. |
| 472 |
|
The ambient file is in a machine-independent binary format |
| 473 |
|
which can be examined with |
| 739 |
|
.IP "" .2i |
| 740 |
|
rtrace \-ov scene.oct < samples.inp > radiance.out |
| 741 |
|
.PP |
| 742 |
< |
To compute illuminance values at locations selected with the 't' |
| 742 |
> |
To compute irradiance values at locations selected with the 't' |
| 743 |
|
command of |
| 744 |
|
.I ximage(1): |
| 745 |
|
.IP "" .2i |
| 754 |
|
cnt 480 640 | rcalc \-e 'xr:640;yr:480' \-f unusual_view.cal | rtrace |
| 755 |
|
\-x 640 \-y 480 \-fac scene.oct > unusual.hdr |
| 756 |
|
.PP |
| 757 |
< |
To compute ambient illuminance in photon mapping mode from a global photon |
| 757 |
> |
To compute ambient irradiance in photon mapping mode from a global photon |
| 758 |
|
map global.pm via one ambient bounce, and from a caustic photon map |
| 759 |
|
caustic.pm at sensor positions in samples.inp: |
| 760 |
|
.IP "" .2i |
