| 211 |
|
Distributed ray-tracing performs anti-aliasing by randomly sampling |
| 212 |
|
over pixels. |
| 213 |
|
A value of one will randomly distribute samples over full |
| 214 |
< |
pixels. |
| 214 |
> |
pixels, and is not really recommended due to the tendency of |
| 215 |
> |
samples to (nearly) coincide. |
| 216 |
|
A value of zero samples pixel centers only. |
| 217 |
< |
A value between zero and one is usually best |
| 217 |
< |
for low-resolution images. |
| 217 |
> |
A value around 0.5-0.8 is typical. |
| 218 |
|
.TP |
| 219 |
|
.BI -pm \ frac |
| 220 |
|
Set the pixel motion blur to |
| 464 |
|
lost when the program finishes or dies. |
| 465 |
|
By using a file, different invocations can share illuminance |
| 466 |
|
values, saving time in the computation. |
| 467 |
< |
Also, by creating an ambient file during a low resolution rendering, |
| 468 |
< |
better results can be obtained in a second high resolution pass. |
| 467 |
> |
Also, by creating an ambient file during a low-resolution rendering, |
| 468 |
> |
better results can be obtained in a second high-resolution pass. |
| 469 |
> |
(It is a good idea to keep all of the calculation parameters the same, |
| 470 |
> |
changing only the dimensions of the output picture.)\0 |
| 471 |
|
The ambient file is in a machine-independent binary format |
| 472 |
|
which may be examined with |
| 473 |
|
.I lookamb(1). |
| 542 |
|
above), caustic photon irradiance is evaluated at primary rays, and |
| 543 |
|
indirect inscattering in |
| 544 |
|
.I mist |
| 545 |
< |
is accounted for by volume photons. |
| 545 |
> |
is accounted for by volume photons. Contribution photons are treated as |
| 546 |
> |
global photons by |
| 547 |
> |
.I rpict. |
| 548 |
|
.IP |
| 549 |
|
Additionally specifying |
| 550 |
|
.I bwidth2 |
| 561 |
|
is invariably looked up. |
| 562 |
|
.IP |
| 563 |
|
Using direct photons replaces the direct calculation with density estimates |
| 564 |
< |
for debugging and validation of photon emission. |
| 564 |
> |
for debugging and validation of photon emission. |
| 565 |
|
.TP |
| 566 |
|
.BI -am " frac" |
| 567 |
|
Maximum search radius for photon map lookups. Without this option, an |
| 597 |
|
.I \-ac. |
| 598 |
|
Note that this is approximate as the number of cache pages is rounded to |
| 599 |
|
the nearest prime. This allows adapting the cache to the available physical |
| 600 |
< |
memory. In conjunction with the |
| 601 |
< |
.I \-n |
| 602 |
< |
option, this is the cache size |
| 603 |
< |
.I per parallel process. |
| 600 |
< |
Cache performance is less sensitive to this parameter, |
| 601 |
< |
and reasonable performance can obtained with as few as 10k photons. The |
| 602 |
< |
default is 1M. This option recognises multiplier suffixes (k = 1e3, M = |
| 603 |
< |
1e6), both in upper and lower case. |
| 600 |
> |
memory. Cache performance is less sensitive to this parameter, and reasonable |
| 601 |
> |
performance can obtained with as few as 10k photons. The default is 1M. This |
| 602 |
> |
option recognises multiplier suffixes (k = 1e3, M = 1e6), both in upper and |
| 603 |
> |
lower case. |
| 604 |
|
.TP |
| 605 |
|
.BI -me " rext gext bext" |
| 606 |
|
Set the global medium extinction coefficient to the indicated color, |
| 664 |
|
termination, and the |
| 665 |
|
.I -lw |
| 666 |
|
setting (below) must be positive. |
| 667 |
< |
If N is a negative integer, then this sets the upper limit |
| 668 |
< |
of reflections past which Russian roulette will be used. |
| 667 |
> |
If N is a negative integer, then this limits the maximum |
| 668 |
> |
number of reflections even with Russian roulette. |
| 669 |
|
In scenes with dielectrics and total internal reflection, |
| 670 |
|
a setting of 0 (no limit) may cause a stack overflow. |
| 671 |
|
.TP |
| 912 |
|
Greg Ward |
| 913 |
|
.SH "SEE ALSO" |
| 914 |
|
getinfo(1), lookamb(1), mkpmap(1), oconv(1), pdfblur(1), pfilt(1), |
| 915 |
< |
pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rtrace(1), rvu(1) |
| 915 |
> |
pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rpiece(1), rtpict(1), rtrace(1), rvu(1) |
