| 70 |
|
to the letter 'c'. |
| 71 |
|
This view is like a standard perspective vertically, but projected |
| 72 |
|
on a cylinder horizontally (like a soupcan's-eye view). |
| 73 |
< |
Two fisheye views are provided as well; 'h' yields a hemispherical fisheye |
| 74 |
< |
view and 'a' results in angular fisheye distortion. |
| 73 |
> |
Three fisheye views are provided as well; 'h' yields a hemispherical fisheye |
| 74 |
> |
view, 'a' results in angular fisheye distortion, and 's' |
| 75 |
> |
results in a planisphere (stereographic) projection. |
| 76 |
|
A hemispherical fisheye is a projection of the hemisphere onto a circle. |
| 77 |
|
The maximum view angle for this type is 180 degrees. |
| 78 |
|
An angular fisheye view is defined such that distance from the center of |
| 79 |
|
the image is proportional to the angle from the central view direction. |
| 80 |
|
An angular fisheye can display a full 360 degrees. |
| 81 |
+ |
A planisphere fisheye view maintains angular relationships between lines, |
| 82 |
+ |
and is commonly used for sun path analysis. |
| 83 |
+ |
This is more commonly known as a |
| 84 |
+ |
"stereographic projection," but we avoid the term here so as not to |
| 85 |
+ |
confuse it with a stereoscopic pair. |
| 86 |
+ |
A planisphere fisheye can display up to (but not including) 360 degrees, |
| 87 |
+ |
although distortion becomes extreme as this limit is approached. |
| 88 |
|
Note that there is no space between the view type |
| 89 |
|
option and its single letter argument. |
| 90 |
|
.TP |
| 160 |
|
rendering an image a piece at a time. |
| 161 |
|
A value of 1 means that the rendered image starts just to the right of |
| 162 |
|
the normal view. |
| 163 |
< |
A value of -1 would be to the left. |
| 163 |
> |
A value of \-1 would be to the left. |
| 164 |
|
Larger or fractional values are permitted as well. |
| 165 |
|
.TP |
| 166 |
|
.BI -vl \ val |
| 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 |
| 209 |
< |
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 |
| 271 |
|
.I frac |
| 272 |
|
is too large. |
| 273 |
|
It is usually wise to turn off image sampling when using |
| 274 |
< |
direct jitter by setting -ps to 1. |
| 274 |
> |
direct jitter by setting \-ps to 1. |
| 275 |
|
.TP |
| 276 |
|
.BI -ds \ frac |
| 277 |
|
Set the direct sampling ratio to |
| 335 |
|
.I \-i |
| 336 |
|
option so that light sources do not appear in the output. |
| 337 |
|
.TP |
| 338 |
< |
.BI -sj \ frac |
| 339 |
< |
Set the specular sampling jitter to |
| 340 |
< |
.I frac. |
| 341 |
< |
This is the degree to which the highlights are sampled |
| 342 |
< |
for rough specular materials. |
| 343 |
< |
A value of one means that all highlights will be fully sampled |
| 344 |
< |
using distributed ray tracing. |
| 338 |
> |
.BI -ss \ samp |
| 339 |
> |
Set the specular sampling to |
| 340 |
> |
.I samp. |
| 341 |
> |
For values less than 1, this is the degree to which the highlights |
| 342 |
> |
are sampled for rough specular materials. |
| 343 |
> |
A value greater than one causes multiple ray samples to be sent |
| 344 |
> |
to reduce noise at a commmesurate cost. |
| 345 |
|
A value of zero means that no jittering will take place, and all |
| 346 |
|
reflections will appear sharp even when they should be diffuse. |
| 347 |
|
This may be desirable when used in combination with image sampling |
| 365 |
|
.TP |
| 366 |
|
.BR -bv |
| 367 |
|
Boolean switch for back face visibility. |
| 368 |
< |
With this switch off, back faces of opaque objects will be invisible |
| 369 |
< |
to all rays. |
| 368 |
> |
With this switch off, back faces of all objects will be invisible |
| 369 |
> |
to view rays. |
| 370 |
|
This is dangerous unless the model was constructed such that |
| 371 |
< |
all surface normals on opaque objects face outward. |
| 371 |
> |
all surface normals face outward. |
| 372 |
|
Although turning off back face visibility does not save much |
| 373 |
|
computation time under most circumstances, it may be useful as a |
| 374 |
|
tool for scene debugging, or for seeing through one-sided walls from |
| 375 |
|
the outside. |
| 368 |
– |
This option has no effect on transparent or translucent materials. |
| 376 |
|
.TP |
| 377 |
|
.BI -av " red grn blu" |
| 378 |
|
Set the ambient value to a radiance of |
| 405 |
|
.BI -ab \ N |
| 406 |
|
Set the number of ambient bounces to |
| 407 |
|
.I N. |
| 408 |
< |
This is the maximum number of diffuse bounces |
| 409 |
< |
computed by the indirect calculation. |
| 410 |
< |
A value of zero implies no indirect calculation. |
| 408 |
> |
This is the maximum number of diffuse bounces computed by the indirect |
| 409 |
> |
calculation. A value of zero implies no indirect calculation. |
| 410 |
> |
.IP |
| 411 |
> |
This value defaults to 1 in photon mapping mode (see |
| 412 |
> |
.I -ap |
| 413 |
> |
below), implying that global photon irradiance is always computed via |
| 414 |
> |
.I one |
| 415 |
> |
ambient bounce; this behaviour applies to any positive number of ambient |
| 416 |
> |
bounces, regardless of the actual value specified. A negative value enables |
| 417 |
> |
a preview mode that directly visualises the irradiance from the global |
| 418 |
> |
photon map without any ambient bounces. |
| 419 |
|
.TP |
| 420 |
|
.BI -ar \ res |
| 421 |
|
Set the ambient resolution 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). |
| 489 |
|
.I Getinfo(1) |
| 490 |
|
may be used to print out this information. |
| 491 |
|
.TP |
| 492 |
< |
.BI -ae \ mat |
| 492 |
> |
.BI -ae \ mod |
| 493 |
|
Append |
| 494 |
< |
.I mat |
| 494 |
> |
.I mod |
| 495 |
|
to the ambient exclude list, |
| 496 |
|
so that it will not be considered during the indirect calculation. |
| 497 |
|
This is a hack for speeding the indirect computation by |
| 498 |
|
ignoring certain objects. |
| 499 |
|
Any object having |
| 500 |
< |
.I mat |
| 500 |
> |
.I mod |
| 501 |
|
as its modifier will get the default ambient |
| 502 |
|
level rather than a calculated value. |
| 503 |
< |
Any number of excluded materials may be given, but each |
| 503 |
> |
Any number of excluded modifiers may be given, but each |
| 504 |
|
must appear in a separate option. |
| 505 |
|
.TP |
| 506 |
< |
.BI -ai \ mat |
| 506 |
> |
.BI -ai \ mod |
| 507 |
|
Add |
| 508 |
< |
.I mat |
| 508 |
> |
.I mod |
| 509 |
|
to the ambient include list, |
| 510 |
|
so that it will be considered during the indirect calculation. |
| 511 |
|
The program can use either an include list or an exclude |
| 514 |
|
.BI -aE \ file |
| 515 |
|
Same as |
| 516 |
|
.I \-ae, |
| 517 |
< |
except read materials to be excluded from |
| 517 |
> |
except read modifiers to be excluded from |
| 518 |
|
.I file. |
| 519 |
|
The RAYPATH environment variable determines which directories are |
| 520 |
|
searched for this file. |
| 521 |
< |
The material names are separated by white space in the file. |
| 521 |
> |
The modifier names are separated by white space in the file. |
| 522 |
|
.TP |
| 523 |
|
.BI -aI \ file |
| 524 |
|
Same as |
| 525 |
|
.I \-ai, |
| 526 |
< |
except read materials to be included from |
| 526 |
> |
except read modifiers to be included from |
| 527 |
|
.I file. |
| 528 |
|
.TP |
| 529 |
+ |
.BI -ap " file [bwidth1 [bwidth2]]" |
| 530 |
+ |
Enable photon mapping mode. Loads a photon map generated with |
| 531 |
+ |
.I mkpmap(1) |
| 532 |
+ |
from |
| 533 |
+ |
.I file, |
| 534 |
+ |
and evaluates the indirect irradiance depending on the photon type |
| 535 |
+ |
(automagically detected) using density estimates with a bandwidth of |
| 536 |
+ |
.I bwidth1 |
| 537 |
+ |
photons, or the default bandwidth if none is specified (a warning will be |
| 538 |
+ |
issued in this case). |
| 539 |
+ |
.IP |
| 540 |
+ |
Global photon irradiance is evaluated as part of the ambient calculation (see |
| 541 |
+ |
.I \-ab |
| 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. Contribution photons are treated as |
| 546 |
+ |
global photons by |
| 547 |
+ |
.I rpict. |
| 548 |
+ |
.IP |
| 549 |
+ |
Additionally specifying |
| 550 |
+ |
.I bwidth2 |
| 551 |
+ |
enables bias compensation for the density estimates with a |
| 552 |
+ |
minimum and maximum bandwidth of |
| 553 |
+ |
.I bwidth1 |
| 554 |
+ |
and |
| 555 |
+ |
.I bwidth2, |
| 556 |
+ |
respectively. |
| 557 |
+ |
.IP |
| 558 |
+ |
Global photon irradiance may be optionally precomputed by |
| 559 |
+ |
.I mkpmap(1), |
| 560 |
+ |
in which case the bandwidth, if specified, is ignored, as the nearest photon |
| 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. |
| 565 |
+ |
.TP |
| 566 |
+ |
.BI -am " frac" |
| 567 |
+ |
Maximum search radius for photon map lookups. Without this option, an |
| 568 |
+ |
initial maximum search radius is estimated for each photon map from the |
| 569 |
+ |
average photon distance to the distribution's centre of gravity. It is then |
| 570 |
+ |
adapted to the photon density in subsequent lookups. This option imposes a |
| 571 |
+ |
global fixed maximum search radius for |
| 572 |
+ |
.I all |
| 573 |
+ |
photon maps, thus defeating the automatic adaptation. It is useful when |
| 574 |
+ |
multiple warnings about short photon lookups are issued. Note that this |
| 575 |
+ |
option does not conflict with the bandwidth specified with the |
| 576 |
+ |
.I \-ap |
| 577 |
+ |
option; the number of photons found will not exceed the latter, but may be |
| 578 |
+ |
lower if the maximum search radius contains fewer photons, thus resulting in |
| 579 |
+ |
short lookups. Setting this radius too large, on the other hand, may |
| 580 |
+ |
degrade performance. |
| 581 |
+ |
.TP |
| 582 |
+ |
.BI -ac " pagesize" |
| 583 |
+ |
Set the photon cache page size when using out-of-core photon mapping. The |
| 584 |
+ |
photon cache reduces disk I/O incurred by on-demand loading (paging) of |
| 585 |
+ |
photons, and thus increases performance. This |
| 586 |
+ |
is expressed as a (float) multiple of the density estimate bandwidth |
| 587 |
+ |
specified with |
| 588 |
+ |
.I \-ap |
| 589 |
+ |
under the assumption that photon lookups are local to a cache page. Cache |
| 590 |
+ |
performance is sensitive to this parameter: larger pagesizes will reduce the |
| 591 |
+ |
paging frequency at the expense of higher latency when paging does occur. |
| 592 |
+ |
Sensible values are in the range 4 (default) to 16. |
| 593 |
+ |
.TP |
| 594 |
+ |
.BI -aC " cachesize" |
| 595 |
+ |
Set the total number of photons cached when using out-of-core photon |
| 596 |
+ |
mapping, taking into account the pagesize specified by |
| 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. 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, |
| 607 |
|
in units of 1/distance (distance in world coordinates). |
| 648 |
|
.I \-dv |
| 649 |
|
option (above) may be used to override this. |
| 650 |
|
.TP |
| 651 |
+ |
.BR \-u |
| 652 |
+ |
Boolean switch to control uncorrelated random sampling. |
| 653 |
+ |
When "off", a low-discrepancy sequence is used, which reduces |
| 654 |
+ |
variance but can result in a dithered appearance in specular highlights. |
| 655 |
+ |
When "on", pure Monte Carlo sampling is used in all calculations. |
| 656 |
+ |
.TP |
| 657 |
|
.BI -lr \ N |
| 658 |
|
Limit reflections to a maximum of |
| 659 |
< |
.I N. |
| 659 |
> |
.I N, |
| 660 |
> |
if N is a positive integer. |
| 661 |
> |
If |
| 662 |
> |
.I N |
| 663 |
> |
is zero, then Russian roulette is used for ray |
| 664 |
> |
termination, and the |
| 665 |
> |
.I -lw |
| 666 |
> |
setting (below) must be positive. |
| 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 |
| 672 |
|
.BI -lw \ frac |
| 673 |
|
Limit the weight of each ray to a minimum of |
| 674 |
|
.I frac. |
| 675 |
< |
During ray-tracing, a record is kept of the final contribution |
| 676 |
< |
a ray would have to the image. |
| 677 |
< |
If it is less then the specified minimum, the ray is not traced. |
| 675 |
> |
During ray-tracing, a record is kept of the estimated contribution |
| 676 |
> |
(weight) a ray would have in the image. |
| 677 |
> |
If this weight is less than the specified minimum and the |
| 678 |
> |
.I -lr |
| 679 |
> |
setting (above) is positive, the ray is not traced. |
| 680 |
> |
Otherwise, Russian roulette is used to |
| 681 |
> |
continue rays with a probability equal to the ray weight |
| 682 |
> |
divided by the given |
| 683 |
> |
.I frac. |
| 684 |
|
.TP |
| 685 |
|
.BI -S \ seqstart |
| 686 |
|
Instead of generating a single picture based only on the view |
| 868 |
|
A progress report writes the number of rays traced, the percentage |
| 869 |
|
completed, and the CPU usage to the standard error. |
| 870 |
|
Reports are given either automatically after the specified interval, |
| 871 |
< |
or when the process receives a continue (-CONT) signal (see |
| 871 |
> |
or when the process receives a continue (\-CONT) signal (see |
| 872 |
|
.I kill(1)). |
| 873 |
|
A value of zero turns automatic reporting off. |
| 874 |
|
.TP |
| 882 |
|
The default is to print warnings, so the first appearance of |
| 883 |
|
this option turns them off. |
| 884 |
|
.SH EXAMPLE |
| 885 |
< |
rpict -vp 10 5 3 -vd 1 -.5 0 scene.oct > scene.pic |
| 885 |
> |
rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.hdr |
| 886 |
|
.PP |
| 887 |
< |
rpict -S 1 -o frame%02d.pic scene.oct < keyframes.vf |
| 887 |
> |
rpict \-S 1 \-o frame%02d.hdr scene.oct < keyframes.vf |
| 888 |
> |
.PP |
| 889 |
> |
To render ambient illuminance in photon mapping mode from a global photon |
| 890 |
> |
map global.pm via one ambient bounce, and from a caustic photon map |
| 891 |
> |
caustic.pm: |
| 892 |
> |
.IP "" .2i |
| 893 |
> |
rpict -ab 1 -ap global.pm 50 -ap caustic.pm 50 -vf scene.vf scene.oct > |
| 894 |
> |
scene.hdr |
| 895 |
|
.SH ENVIRONMENT |
| 896 |
|
RAYPATH the directories to check for auxiliary files. |
| 897 |
|
.SH FILES |
| 898 |
< |
/usr/tmp/rtXXXXXX common header information for picture sequence |
| 898 |
> |
/tmp/rtXXXXXX common header information for picture sequence |
| 899 |
|
.br |
| 900 |
|
rfXXXXXX temporary name for recover file |
| 901 |
|
.SH DIAGNOSTICS |
| 911 |
|
.SH AUTHOR |
| 912 |
|
Greg Ward |
| 913 |
|
.SH "SEE ALSO" |
| 914 |
< |
getinfo(1), lookamb(1), oconv(1), pdfblur(1), pfilt(1), pinterp(1), pmblur(1), |
| 915 |
< |
printf(3), ra_rgbe(1), rad(1), rtrace(1), rvu(1) |
| 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), rpiece(1), rtpict(1), rtrace(1), rvu(1) |
