| 68 |
|
ascii, 'f' for single-precision floating point, |
| 69 |
|
and 'd' for double-precision floating point. |
| 70 |
|
In addition to these three choices, the character 'c' may be used |
| 71 |
< |
to denote 4-byte floating point (Radiance) color format |
| 72 |
< |
for the output of values only |
| 73 |
< |
.I (\-ov |
| 74 |
< |
option, below). |
| 71 |
> |
to denote 4-byte RGBE (Radiance) color format |
| 72 |
> |
for the output of individual color values only, and the |
| 73 |
> |
.I \-x |
| 74 |
> |
and |
| 75 |
> |
.I \-y |
| 76 |
> |
options should also be specified to create a valid output picture. |
| 77 |
|
If the output character is missing, the input format is used. |
| 78 |
|
.IP |
| 79 |
|
Note that there is no space between this option and its argument. |
| 113 |
|
.IP |
| 114 |
|
M material name |
| 115 |
|
.IP |
| 116 |
+ |
r mirrored value contribution |
| 117 |
+ |
.IP |
| 118 |
+ |
x unmirrored value contribution |
| 119 |
+ |
.IP |
| 120 |
+ |
R mirrored ray length |
| 121 |
+ |
.IP |
| 122 |
+ |
X unmirrored ray length |
| 123 |
+ |
.IP |
| 124 |
|
~ tilde (end of trace marker) |
| 125 |
|
.IP |
| 126 |
|
If the letter 't' appears in |
| 543 |
|
above), caustic photon irradiance is evaluated at primary rays, and |
| 544 |
|
indirect inscattering in |
| 545 |
|
.I mist |
| 546 |
< |
is accounted for by volume photons. |
| 546 |
> |
is accounted for by volume photons. Contribution photons are treated as |
| 547 |
> |
global photons by |
| 548 |
> |
.I rtrace. |
| 549 |
|
.IP |
| 550 |
|
Additionally specifying |
| 551 |
|
.I bwidth2 |
| 580 |
|
short lookups. Setting this radius too large, on the other hand, may |
| 581 |
|
degrade performance. |
| 582 |
|
.TP |
| 583 |
+ |
.BI -ac " pagesize" |
| 584 |
+ |
Set the photon cache page size when using out-of-core photon mapping. The |
| 585 |
+ |
photon cache reduces disk I/O incurred by on-demand loading (paging) of |
| 586 |
+ |
photons, and thus increases performance. This |
| 587 |
+ |
is expressed as a (float) multiple of the density estimate bandwidth |
| 588 |
+ |
specified with |
| 589 |
+ |
.I \-ap |
| 590 |
+ |
under the assumption that photon lookups are local to a cache page. Cache |
| 591 |
+ |
performance is sensitive to this parameter: larger pagesizes will reduce the |
| 592 |
+ |
paging frequency at the expense of higher latency when paging does occur. |
| 593 |
+ |
Sensible values are in the range 4 (default) to 16. |
| 594 |
+ |
.TP |
| 595 |
+ |
.BI -aC " cachesize" |
| 596 |
+ |
Set the total number of photons cached when using out-of-core photon |
| 597 |
+ |
mapping, taking into account the pagesize specified by |
| 598 |
+ |
.I \-ac. |
| 599 |
+ |
Note that this is approximate as the number of cache pages is rounded to |
| 600 |
+ |
the nearest prime. This allows adapting the cache to the available physical |
| 601 |
+ |
memory. In conjunction with the |
| 602 |
+ |
.I \-n |
| 603 |
+ |
option, this is the cache size |
| 604 |
+ |
.I per parallel process. |
| 605 |
+ |
Cache performance is less sensitive to this parameter, |
| 606 |
+ |
and reasonable performance can obtained with as few as 10k photons. The |
| 607 |
+ |
default is 1M. This option recognises multiplier suffixes (k = 1e3, M = |
| 608 |
+ |
1e6), both in upper and lower case. |
| 609 |
+ |
.TP |
| 610 |
|
.BI -me " rext gext bext" |
| 611 |
|
Set the global medium extinction coefficient to the indicated color, |
| 612 |
|
in units of 1/distance (distance in world coordinates). |
| 653 |
|
termination, and the |
| 654 |
|
.I -lw |
| 655 |
|
setting (below) must be positive. |
| 656 |
< |
If N is a negative integer, then this sets the upper limit |
| 657 |
< |
of reflections past which Russian roulette will be used. |
| 656 |
> |
If N is a negative integer, then this limits the maximum |
| 657 |
> |
number of reflections even with Russian roulette. |
| 658 |
|
In scenes with dielectrics and total internal reflection, |
| 659 |
|
a setting of 0 (no limit) may cause a stack overflow. |
| 660 |
|
.TP |
| 778 |
|
Greg Ward |
| 779 |
|
.SH "SEE ALSO" |
| 780 |
|
getinfo(1), lookamb(1), mkpmap(1), oconv(1), pfilt(1), pinterp(1), |
| 781 |
< |
pvalue(1), rpict(1), rcontrib(1), rvu(1), vwrays(1), ximage(1) |
| 781 |
> |
pvalue(1), rcontrib(1), rpict(1), rtpict(1), rvu(1), vwrays(1), ximage(1) |
