| 18 |
|
] |
| 19 |
|
.br |
| 20 |
|
.B "rpict [ options ] \-defaults" |
| 21 |
+ |
.br |
| 22 |
+ |
.B "rpict \-features [feat1 ..]" |
| 23 |
|
.SH DESCRIPTION |
| 24 |
|
.I Rpict |
| 25 |
|
generates a picture from the RADIANCE scene given in |
| 43 |
|
for the options (modified by those options present) |
| 44 |
|
are printed with a brief explanation. |
| 45 |
|
.PP |
| 46 |
+ |
In the third form, a list of supported features is sent |
| 47 |
+ |
to the standard output, one per line. |
| 48 |
+ |
If additional arguments follow, they are checked for presence in |
| 49 |
+ |
this list. |
| 50 |
+ |
If a feature includes subfeatures, these may be checked as well by |
| 51 |
+ |
specifying: |
| 52 |
+ |
.nf |
| 53 |
+ |
|
| 54 |
+ |
rpict -features FeatName=subfeat1,subfeat2 |
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+ |
|
| 56 |
+ |
.fi |
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+ |
If any named feature or subfeature is missing, an error is |
| 58 |
+ |
reported and the program returns an error status. |
| 59 |
+ |
If all of the named features are present, a zero status is returned. |
| 60 |
+ |
.PP |
| 61 |
|
Most options are followed by one or more arguments, which must be |
| 62 |
|
separated from the option and each other by white space. |
| 63 |
|
The exceptions to this rule are the |
| 228 |
|
Distributed ray-tracing performs anti-aliasing by randomly sampling |
| 229 |
|
over pixels. |
| 230 |
|
A value of one will randomly distribute samples over full |
| 231 |
< |
pixels. |
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> |
pixels, and is not really recommended due to the tendency of |
| 232 |
> |
samples to (nearly) coincide. |
| 233 |
|
A value of zero samples pixel centers only. |
| 234 |
< |
A value between zero and one is usually best |
| 217 |
< |
for low-resolution images. |
| 234 |
> |
A value around 0.5-0.8 is typical. |
| 235 |
|
.TP |
| 236 |
|
.BI -pm \ frac |
| 237 |
|
Set the pixel motion blur to |
| 271 |
|
.I \-pd |
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|
option, to avoid the ghosting effect of too few samples. |
| 273 |
|
.TP |
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+ |
.BI -pc " xr yr xg yg xb yb xw yw" |
| 275 |
+ |
Use the specified chromaticity pairs for output primaries and white |
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+ |
point rather than the standard RGB color space. |
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+ |
.TP |
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+ |
.BR \-pRGB |
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+ |
Output standard RGB values (the default). |
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+ |
.TP |
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+ |
.BR \-pXYZ |
| 282 |
+ |
Output standard CIE XYZ tristimulus values rather than RGB. |
| 283 |
+ |
.TP |
| 284 |
|
.BI -dj \ frac |
| 285 |
|
Set the direct jittering to |
| 286 |
|
.I frac. |
| 337 |
|
specification will be calculated. |
| 338 |
|
.TP |
| 339 |
|
.BI -dr \ N |
| 340 |
< |
Set the number of relays for secondary sources to |
| 340 |
> |
Set the number of relays for virtual sources to |
| 341 |
|
.I N. |
| 342 |
< |
A value of 0 means that secondary sources will be ignored. |
| 342 |
> |
A value of 0 means that virtual sources will be ignored. |
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|
A value of 1 means that sources will be made into first generation |
| 344 |
< |
secondary sources; a value of 2 means that first generation |
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< |
secondary sources will also be made into second generation secondary |
| 344 |
> |
virtual sources; a value of 2 means that first generation |
| 345 |
> |
virtual sources will also be made into second generation virtual |
| 346 |
|
sources, and so on. |
| 347 |
|
.TP |
| 348 |
|
.BI -dp \ D |
| 349 |
< |
Set the secondary source presampling density to D. |
| 349 |
> |
Set the virtual source presampling density to D. |
| 350 |
|
This is the number of samples per steradian |
| 351 |
|
that will be used to determine ahead of time whether or not |
| 352 |
|
it is worth following shadow rays through all the reflections and/or |
| 353 |
< |
transmissions associated with a secondary source path. |
| 354 |
< |
A value of 0 means that the full secondary source path will always |
| 353 |
> |
transmissions associated with a virtual source path. |
| 354 |
> |
A value of 0 means that the full virtual source path will always |
| 355 |
|
be tested for shadows if it is tested at all. |
| 356 |
|
.TP |
| 357 |
|
.BR \-dv |
| 362 |
|
.I \-i |
| 363 |
|
option so that light sources do not appear in the output. |
| 364 |
|
.TP |
| 365 |
< |
.BI -sj \ frac |
| 366 |
< |
Set the specular sampling jitter to |
| 367 |
< |
.I frac. |
| 368 |
< |
This is the degree to which the highlights are sampled |
| 369 |
< |
for rough specular materials. |
| 370 |
< |
A value of one means that all highlights will be fully sampled |
| 371 |
< |
using distributed ray tracing. |
| 365 |
> |
.BI -ss \ samp |
| 366 |
> |
Set the specular sampling to |
| 367 |
> |
.I samp. |
| 368 |
> |
For values less than 1, this is the degree to which the highlights |
| 369 |
> |
are sampled for rough specular materials. |
| 370 |
> |
A value greater than one causes multiple ray samples to be sent |
| 371 |
> |
to reduce noise at a commmesurate cost. |
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|
A value of zero means that no jittering will take place, and all |
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|
reflections will appear sharp even when they should be diffuse. |
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|
This may be desirable when used in combination with image sampling |
| 392 |
|
.TP |
| 393 |
|
.BR -bv |
| 394 |
|
Boolean switch for back face visibility. |
| 395 |
< |
With this switch off, back faces of opaque objects will be invisible |
| 396 |
< |
to all rays. |
| 395 |
> |
With this switch off, back faces of all objects will be invisible |
| 396 |
> |
to view rays. |
| 397 |
|
This is dangerous unless the model was constructed such that |
| 398 |
< |
all surface normals on opaque objects face outward. |
| 398 |
> |
all surface normals face outward. |
| 399 |
|
Although turning off back face visibility does not save much |
| 400 |
|
computation time under most circumstances, it may be useful as a |
| 401 |
|
tool for scene debugging, or for seeing through one-sided walls from |
| 402 |
|
the outside. |
| 376 |
– |
This option has no effect on transparent or translucent materials. |
| 403 |
|
.TP |
| 404 |
|
.BI -av " red grn blu" |
| 405 |
|
Set the ambient value to a radiance of |
| 432 |
|
.BI -ab \ N |
| 433 |
|
Set the number of ambient bounces to |
| 434 |
|
.I N. |
| 435 |
< |
This is the maximum number of diffuse bounces |
| 436 |
< |
computed by the indirect calculation. |
| 437 |
< |
A value of zero implies no indirect calculation. |
| 435 |
> |
This is the maximum number of diffuse bounces computed by the indirect |
| 436 |
> |
calculation. A value of zero implies no indirect calculation. |
| 437 |
> |
.IP |
| 438 |
> |
This value defaults to 1 in photon mapping mode (see |
| 439 |
> |
.I -ap |
| 440 |
> |
below), implying that global photon irradiance is always computed via |
| 441 |
> |
.I one |
| 442 |
> |
ambient bounce; this behaviour applies to any positive number of ambient |
| 443 |
> |
bounces, regardless of the actual value specified. A negative value enables |
| 444 |
> |
a preview mode that directly visualises the irradiance from the global |
| 445 |
> |
photon map without any ambient bounces. |
| 446 |
|
.TP |
| 447 |
|
.BI -ar \ res |
| 448 |
|
Set the ambient resolution to |
| 466 |
|
Set the ambient accuracy to |
| 467 |
|
.I acc. |
| 468 |
|
This value will approximately equal the error |
| 469 |
< |
from indirect illuminance interpolation. |
| 469 |
> |
from indirect irradiance interpolation. |
| 470 |
|
A value of zero implies no interpolation. |
| 471 |
|
.TP |
| 472 |
|
.BI -ad \ N |
| 473 |
|
Set the number of ambient divisions to |
| 474 |
|
.I N. |
| 475 |
|
The error in the Monte Carlo calculation of indirect |
| 476 |
< |
illuminance will be inversely proportional to the square |
| 476 |
> |
irradiance will be inversely proportional to the square |
| 477 |
|
root of this number. |
| 478 |
|
A value of zero implies no indirect calculation. |
| 479 |
|
.TP |
| 486 |
|
.BI -af \ fname |
| 487 |
|
Set the ambient file to |
| 488 |
|
.I fname. |
| 489 |
< |
This is where indirect illuminance will be stored and retrieved. |
| 490 |
< |
Normally, indirect illuminance values are kept in memory and |
| 489 |
> |
This is where indirect irradiance will be stored and retrieved. |
| 490 |
> |
Normally, indirect irradiance values are kept in memory and |
| 491 |
|
lost when the program finishes or dies. |
| 492 |
< |
By using a file, different invocations can share illuminance |
| 492 |
> |
By using a file, different invocations can share irradiance |
| 493 |
|
values, saving time in the computation. |
| 494 |
< |
Also, by creating an ambient file during a low resolution rendering, |
| 495 |
< |
better results can be obtained in a second high resolution pass. |
| 494 |
> |
Also, by creating an ambient file during a low-resolution rendering, |
| 495 |
> |
better results can be obtained in a second high-resolution pass. |
| 496 |
> |
(It is a good idea to keep all of the calculation parameters the same, |
| 497 |
> |
changing only the dimensions of the output picture.)\0 |
| 498 |
|
The ambient file is in a machine-independent binary format |
| 499 |
|
which may be examined with |
| 500 |
|
.I lookamb(1). |
| 553 |
|
except read modifiers to be included from |
| 554 |
|
.I file. |
| 555 |
|
.TP |
| 556 |
+ |
.BI -ap " file [bwidth1 [bwidth2]]" |
| 557 |
+ |
Enable photon mapping mode. Loads a photon map generated with |
| 558 |
+ |
.I mkpmap(1) |
| 559 |
+ |
from |
| 560 |
+ |
.I file, |
| 561 |
+ |
and evaluates the indirect irradiance depending on the photon type |
| 562 |
+ |
(automagically detected) using density estimates with a bandwidth of |
| 563 |
+ |
.I bwidth1 |
| 564 |
+ |
photons, or the default bandwidth if none is specified (a warning will be |
| 565 |
+ |
issued in this case). |
| 566 |
+ |
.IP |
| 567 |
+ |
Global photon irradiance is evaluated as part of the ambient calculation (see |
| 568 |
+ |
.I \-ab |
| 569 |
+ |
above), caustic photon irradiance is evaluated at primary rays, and |
| 570 |
+ |
indirect inscattering in |
| 571 |
+ |
.I mist |
| 572 |
+ |
is accounted for by volume photons. Contribution photons are treated as |
| 573 |
+ |
global photons by |
| 574 |
+ |
.I rpict. |
| 575 |
+ |
.IP |
| 576 |
+ |
Additionally specifying |
| 577 |
+ |
.I bwidth2 |
| 578 |
+ |
enables bias compensation for the density estimates with a |
| 579 |
+ |
minimum and maximum bandwidth of |
| 580 |
+ |
.I bwidth1 |
| 581 |
+ |
and |
| 582 |
+ |
.I bwidth2, |
| 583 |
+ |
respectively. |
| 584 |
+ |
.IP |
| 585 |
+ |
Global photon irradiance may be optionally precomputed by |
| 586 |
+ |
.I mkpmap(1), |
| 587 |
+ |
in which case the bandwidth, if specified, is ignored, as the nearest photon |
| 588 |
+ |
is invariably looked up. |
| 589 |
+ |
.IP |
| 590 |
+ |
Using direct photons replaces the direct calculation with density estimates |
| 591 |
+ |
for debugging and validation of photon emission. |
| 592 |
+ |
.TP |
| 593 |
+ |
.BI -am " frac" |
| 594 |
+ |
Maximum search radius for photon map lookups. Without this option, an |
| 595 |
+ |
initial maximum search radius is estimated for each photon map from the |
| 596 |
+ |
average photon distance to the distribution's centre of gravity. It is then |
| 597 |
+ |
adapted to the photon density in subsequent lookups. This option imposes a |
| 598 |
+ |
global fixed maximum search radius for |
| 599 |
+ |
.I all |
| 600 |
+ |
photon maps, thus defeating the automatic adaptation. It is useful when |
| 601 |
+ |
multiple warnings about short photon lookups are issued. Note that this |
| 602 |
+ |
option does not conflict with the bandwidth specified with the |
| 603 |
+ |
.I \-ap |
| 604 |
+ |
option; the number of photons found will not exceed the latter, but may be |
| 605 |
+ |
lower if the maximum search radius contains fewer photons, thus resulting in |
| 606 |
+ |
short lookups. Setting this radius too large, on the other hand, may |
| 607 |
+ |
degrade performance. |
| 608 |
+ |
.TP |
| 609 |
+ |
.BI -ac " pagesize" |
| 610 |
+ |
Set the photon cache page size when using out-of-core photon mapping. The |
| 611 |
+ |
photon cache reduces disk I/O incurred by on-demand loading (paging) of |
| 612 |
+ |
photons, and thus increases performance. This |
| 613 |
+ |
is expressed as a (float) multiple of the density estimate bandwidth |
| 614 |
+ |
specified with |
| 615 |
+ |
.I \-ap |
| 616 |
+ |
under the assumption that photon lookups are local to a cache page. Cache |
| 617 |
+ |
performance is sensitive to this parameter: larger pagesizes will reduce the |
| 618 |
+ |
paging frequency at the expense of higher latency when paging does occur. |
| 619 |
+ |
Sensible values are in the range 4 (default) to 16. |
| 620 |
+ |
.TP |
| 621 |
+ |
.BI -aC " cachesize" |
| 622 |
+ |
Set the total number of photons cached when using out-of-core photon |
| 623 |
+ |
mapping, taking into account the pagesize specified by |
| 624 |
+ |
.I \-ac. |
| 625 |
+ |
Note that this is approximate as the number of cache pages is rounded to |
| 626 |
+ |
the nearest prime. This allows adapting the cache to the available physical |
| 627 |
+ |
memory. Cache performance is less sensitive to this parameter, and reasonable |
| 628 |
+ |
performance can obtained with as few as 10k photons. The default is 1M. This |
| 629 |
+ |
option recognises multiplier suffixes (k = 1e3, M = 1e6), both in upper and |
| 630 |
+ |
lower case. |
| 631 |
+ |
.TP |
| 632 |
|
.BI -me " rext gext bext" |
| 633 |
|
Set the global medium extinction coefficient to the indicated color, |
| 634 |
|
in units of 1/distance (distance in world coordinates). |
| 678 |
|
.BR \-u |
| 679 |
|
Boolean switch to control uncorrelated random sampling. |
| 680 |
|
When "off", a low-discrepancy sequence is used, which reduces |
| 681 |
< |
variance but can result in a brushed appearance in specular highlights. |
| 681 |
> |
variance but can result in a dithered appearance in specular highlights. |
| 682 |
|
When "on", pure Monte Carlo sampling is used in all calculations. |
| 683 |
|
.TP |
| 684 |
|
.BI -lr \ N |
| 685 |
|
Limit reflections to a maximum of |
| 686 |
< |
.I N. |
| 686 |
> |
.I N, |
| 687 |
> |
if N is a positive integer. |
| 688 |
|
If |
| 689 |
|
.I N |
| 690 |
|
is zero, then Russian roulette is used for ray |
| 691 |
|
termination, and the |
| 692 |
|
.I -lw |
| 693 |
|
setting (below) must be positive. |
| 694 |
< |
If N is a negative integer, then this sets the upper limit |
| 695 |
< |
of reflections past which Russian roulette will not be used. |
| 694 |
> |
If N is a negative integer, then this limits the maximum |
| 695 |
> |
number of reflections even with Russian roulette. |
| 696 |
|
In scenes with dielectrics and total internal reflection, |
| 697 |
|
a setting of 0 (no limit) may cause a stack overflow. |
| 698 |
|
.TP |
| 709 |
|
divided by the given |
| 710 |
|
.I frac. |
| 711 |
|
.TP |
| 712 |
+ |
.BI -cs \ Ns |
| 713 |
+ |
Use |
| 714 |
+ |
.I Ns |
| 715 |
+ |
bands for spectral sampling rather than the default RGB calculation space. |
| 716 |
+ |
The maximum setting is controlled by the compiler macro MAXCSAMP, and |
| 717 |
+ |
defaults to 24. |
| 718 |
+ |
Larger values for Ns will be reduced to MAXCSAMP. |
| 719 |
+ |
.TP |
| 720 |
+ |
.BI -cw " nmA nmB" |
| 721 |
+ |
Set extrema to the given wavelengths for spectral sampling. |
| 722 |
+ |
The default is 380 and 780 nanometers. |
| 723 |
+ |
The order specified does not matter. |
| 724 |
+ |
.TP |
| 725 |
|
.BI -S \ seqstart |
| 726 |
|
Instead of generating a single picture based only on the view |
| 727 |
|
parameters given on the command line, this option causes |
| 925 |
|
rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.hdr |
| 926 |
|
.PP |
| 927 |
|
rpict \-S 1 \-o frame%02d.hdr scene.oct < keyframes.vf |
| 928 |
+ |
.PP |
| 929 |
+ |
To render ambient irradiance in photon mapping mode from a global photon |
| 930 |
+ |
map global.pm via one ambient bounce, and from a caustic photon map |
| 931 |
+ |
caustic.pm: |
| 932 |
+ |
.IP "" .2i |
| 933 |
+ |
rpict -ab 1 -ap global.pm 50 -ap caustic.pm 50 -vf scene.vf scene.oct > |
| 934 |
+ |
scene.hdr |
| 935 |
|
.SH ENVIRONMENT |
| 936 |
|
RAYPATH the directories to check for auxiliary files. |
| 937 |
|
.SH FILES |
| 951 |
|
.SH AUTHOR |
| 952 |
|
Greg Ward |
| 953 |
|
.SH "SEE ALSO" |
| 954 |
< |
getinfo(1), lookamb(1), oconv(1), pdfblur(1), pfilt(1), pinterp(1), pmblur(1), |
| 955 |
< |
printf(3), ra_rgbe(1), rad(1), rtrace(1), rvu(1) |
| 954 |
> |
getinfo(1), lookamb(1), mkpmap(1), oconv(1), pdfblur(1), pfilt(1), |
| 955 |
> |
pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rpiece(1), rtpict(1), rtrace(1), rvu(1) |
