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# Line 1 | Line 1
1 < .\" RCSid "$Id"
1 > .\" RCSid "$Id$"
2   .TH RPICT 1 2/26/99 RADIANCE
3   .SH NAME
4   rpict - generate a RADIANCE picture
# Line 18 | Line 18 | rpict - generate a RADIANCE picture
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
# Line 41 | Line 43 | In the second form shown above, the default values
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
55 +
56 + .fi
57 + 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
# Line 70 | Line 87 | A cylindrical panorma may be selected by setting
87   to the letter 'c'.
88   This view is like a standard perspective vertically, but projected
89   on a cylinder horizontally (like a soupcan's-eye view).
90 < Two fisheye views are provided as well; 'h' yields a hemispherical fisheye
91 < view and 'a' results in angular fisheye distortion.
90 > Three fisheye views are provided as well; 'h' yields a hemispherical fisheye
91 > view, 'a' results in angular fisheye distortion, and 's'
92 > results in a planisphere (stereographic) projection.
93   A hemispherical fisheye is a projection of the hemisphere onto a circle.
94   The maximum view angle for this type is 180 degrees.
95   An angular fisheye view is defined such that distance from the center of
96   the image is proportional to the angle from the central view direction.
97   An angular fisheye can display a full 360 degrees.
98 + A planisphere fisheye view maintains angular relationships between lines,
99 + and is commonly used for sun path analysis.
100 + This is more commonly known as a
101 + "stereographic projection," but we avoid the term here so as not to
102 + confuse it with a stereoscopic pair.
103 + A planisphere fisheye can display up to (but not including) 360 degrees,
104 + although distortion becomes extreme as this limit is approached.
105   Note that there is no space between the view type
106   option and its single letter argument.
107   .TP
# Line 89 | Line 114 | center of a parallel projection.
114   .BI -vd " xd yd zd"
115   Set the view direction vector to
116   .I "xd yd zd".
117 + The length of this vector indicates the focal distance as needed by the
118 + .I \-pd
119 + option, described below.
120   .TP
121   .BI -vu " xd yd zd"
122   Set the view up vector (vertical direction) to
# Line 149 | Line 177 | This is option is useful for generating skewed perspec
177   rendering an image a piece at a time.
178   A value of 1 means that the rendered image starts just to the right of
179   the normal view.
180 < A value of -1 would be to the left.
180 > A value of \-1 would be to the left.
181   Larger or fractional values are permitted as well.
182   .TP
183   .BI -vl \ val
# Line 163 | Line 191 | option.
191   .BI -vf \ file
192   Get view parameters from
193   .I file,
194 < which may be a picture or a file created by rview (with the "view" command).
194 > which may be a picture or a file created by rvu (with the "view" command).
195   .TP
196   .BI -x \ res
197   Set the maximum x resolution to
# Line 200 | Line 228 | Set the pixel sample jitter to
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.
231 > 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
206 < 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
# Line 226 | Line 254 | to use a very small fraction with the
254   .I \-pm
255   option, to avoid the ghosting effect of too few time samples.
256   .TP
257 + .BI -pd \ dia
258 + Set the pixel depth-of-field aperture to a diameter of
259 + .I dia
260 + (in world coordinates).
261 + This will be used in conjunction with the view focal distance, indicated
262 + by the length of the view direction vector given in the
263 + .I \-vd
264 + option.
265 + It is not advisable to use this option in combination with the
266 + .I pdfblur(1)
267 + program, since one takes the place of the other.
268 + However, it may improve results with
269 + .I pdfblur
270 + to use a very small fraction with the
271 + .I \-pd
272 + option, to avoid the ghosting effect of too few samples.
273 + .TP
274 + .BI -pc " xr yr xg yg xb yb xw yw"
275 + Use the specified chromaticity pairs for output primaries and white
276 + point rather than the standard RGB color space.
277 + .TP
278 + .BR \-pRGB
279 + Output standard RGB values (the default).
280 + .TP
281 + .BR \-pXYZ
282 + Output standard CIE XYZ tristimulus values rather than RGB.
283 + .TP
284 + .BI -f \ source
285 + Load definitions from the file
286 + .I source
287 + and assign at the global level.
288 + The usual set of library directories is searched based on the
289 + .I RAYPATH
290 + environment variable.
291 + .TP
292 + .BI -e \ expr
293 + Set additional definitions from
294 + .I expr.
295 + .TP
296   .BI -dj \ frac
297   Set the direct jittering to
298   .I frac.
# Line 243 | Line 310 | A warning about aiming failure will issued if
310   .I frac
311   is too large.
312   It is usually wise to turn off image sampling when using
313 < direct jitter by setting -ps to 1.
313 > direct jitter by setting \-ps to 1.
314   .TP
315   .BI -ds \ frac
316   Set the direct sampling ratio to
# Line 282 | Line 349 | change greater than the
349   specification will be calculated.
350   .TP
351   .BI -dr \ N
352 < Set the number of relays for secondary sources to
352 > Set the number of relays for virtual sources to
353   .I N.
354 < A value of 0 means that secondary sources will be ignored.
354 > A value of 0 means that virtual sources will be ignored.
355   A value of 1 means that sources will be made into first generation
356 < secondary sources; a value of 2 means that first generation
357 < secondary sources will also be made into second generation secondary
356 > virtual sources; a value of 2 means that first generation
357 > virtual sources will also be made into second generation virtual
358   sources, and so on.
359   .TP
360   .BI -dp \ D
361 < Set the secondary source presampling density to D.
361 > Set the virtual source presampling density to D.
362   This is the number of samples per steradian
363   that will be used to determine ahead of time whether or not
364   it is worth following shadow rays through all the reflections and/or
365 < transmissions associated with a secondary source path.
366 < A value of 0 means that the full secondary source path will always
365 > transmissions associated with a virtual source path.
366 > A value of 0 means that the full virtual source path will always
367   be tested for shadows if it is tested at all.
368   .TP
369   .BR \-dv
# Line 307 | Line 374 | This option may be desirable in conjunction with the
374   .I \-i
375   option so that light sources do not appear in the output.
376   .TP
377 < .BI -sj \ frac
378 < Set the specular sampling jitter to
379 < .I frac.
380 < This is the degree to which the highlights are sampled
381 < for rough specular materials.
382 < A value of one means that all highlights will be fully sampled
383 < using distributed ray tracing.
377 > .BI -ss \ samp
378 > Set the specular sampling to
379 > .I samp.
380 > For values less than 1, this is the degree to which the highlights
381 > are sampled for rough specular materials.
382 > A value greater than one causes multiple ray samples to be sent
383 > to reduce noise at a commmesurate cost.
384   A value of zero means that no jittering will take place, and all
385   reflections will appear sharp even when they should be diffuse.
386   This may be desirable when used in combination with image sampling
# Line 337 | Line 404 | accuracy and rendering time.
404   .TP
405   .BR -bv
406   Boolean switch for back face visibility.
407 < With this switch off, back faces of opaque objects will be invisible
408 < to all rays.
407 > With this switch off, back faces of all objects will be invisible
408 > to view rays.
409   This is dangerous unless the model was constructed such that
410 < all surface normals on opaque objects face outward.
410 > all surface normals face outward.
411   Although turning off back face visibility does not save much
412   computation time under most circumstances, it may be useful as a
413   tool for scene debugging, or for seeing through one-sided walls from
414   the outside.
348 This option has no effect on transparent or translucent materials.
415   .TP
416   .BI -av " red grn blu"
417   Set the ambient value to a radiance of
# Line 378 | Line 444 | indirect contributions, such as when both indoor and o
444   .BI -ab \ N
445   Set the number of ambient bounces to
446   .I N.
447 < This is the maximum number of diffuse bounces
448 < computed by the indirect calculation.
449 < A value of zero implies no indirect calculation.
447 > This is the maximum number of diffuse bounces computed by the indirect
448 > calculation. A value of zero implies no indirect calculation.
449 > .IP
450 > This value defaults to 1 in photon mapping mode (see
451 > .I -ap
452 > below), implying that global photon irradiance is always computed via
453 > .I one
454 > ambient bounce; this behaviour applies to any positive number of ambient
455 > bounces, regardless of the actual value specified.  A negative value enables
456 > a preview mode that directly visualises the irradiance from the global
457 > photon map without any ambient bounces.
458   .TP
459   .BI -ar \ res
460   Set the ambient resolution to
# Line 404 | Line 478 | A value of zero is interpreted as unlimited resolution
478   Set the ambient accuracy to
479   .I acc.
480   This value will approximately equal the error
481 < from indirect illuminance interpolation.
481 > from indirect irradiance interpolation.
482   A value of zero implies no interpolation.
483   .TP
484   .BI -ad \ N
485   Set the number of ambient divisions to
486   .I N.
487   The error in the Monte Carlo calculation of indirect
488 < illuminance will be inversely proportional to the square
488 > irradiance will be inversely proportional to the square
489   root of this number.
490   A value of zero implies no indirect calculation.
491   .TP
# Line 424 | Line 498 | show a significant change.
498   .BI -af \ fname
499   Set the ambient file to
500   .I fname.
501 < This is where indirect illuminance will be stored and retrieved.
502 < Normally, indirect illuminance values are kept in memory and
501 > This is where indirect irradiance will be stored and retrieved.
502 > Normally, indirect irradiance values are kept in memory and
503   lost when the program finishes or dies.
504 < By using a file, different invocations can share illuminance
504 > By using a file, different invocations can share irradiance
505   values, saving time in the computation.
506 < Also, by creating an ambient file during a low resolution rendering,
507 < better results can be obtained in a second high resolution pass.
506 > Also, by creating an ambient file during a low-resolution rendering,
507 > better results can be obtained in a second high-resolution pass.
508 > (It is a good idea to keep all of the calculation parameters the same,
509 > changing only the dimensions of the output picture.)\0
510   The ambient file is in a machine-independent binary format
511   which may be examined with
512   .I lookamb(1).
# Line 452 | Line 528 | header of the ambient file.
528   .I Getinfo(1)
529   may be used to print out this information.
530   .TP
531 < .BI -ae \ mat
531 > .BI -ae \ mod
532   Append
533 < .I mat
533 > .I mod
534   to the ambient exclude list,
535   so that it will not be considered during the indirect calculation.
536   This is a hack for speeding the indirect computation by
537   ignoring certain objects.
538   Any object having
539 < .I mat
539 > .I mod
540   as its modifier will get the default ambient
541   level rather than a calculated value.
542 < Any number of excluded materials may be given, but each
542 > Any number of excluded modifiers may be given, but each
543   must appear in a separate option.
544   .TP
545 < .BI -ai \ mat
545 > .BI -ai \ mod
546   Add
547 < .I mat
547 > .I mod
548   to the ambient include list,
549   so that it will be considered during the indirect calculation.
550   The program can use either an include list or an exclude
# Line 477 | Line 553 | list, but not both.
553   .BI -aE \ file
554   Same as
555   .I \-ae,
556 < except read materials to be excluded from
556 > except read modifiers to be excluded from
557   .I file.
558   The RAYPATH environment variable determines which directories are
559   searched for this file.
560 < The material names are separated by white space in the file.
560 > The modifier names are separated by white space in the file.
561   .TP
562   .BI -aI \ file
563   Same as
564   .I \-ai,
565 < except read materials to be included from
565 > except read modifiers to be included from
566   .I file.
567   .TP
568 + .BI -ap " file [bwidth1 [bwidth2]]"
569 + Enable photon mapping mode. Loads a photon map generated with
570 + .I mkpmap(1)
571 + from
572 + .I file,
573 + and evaluates the indirect irradiance depending on the photon type
574 + (automagically detected) using density estimates with a bandwidth of
575 + .I bwidth1
576 + photons, or the default bandwidth if none is specified (a warning will be
577 + issued in this case).
578 + .IP
579 + Global photon irradiance is evaluated as part of the ambient calculation (see
580 + .I \-ab
581 + above), caustic photon irradiance is evaluated at primary rays, and
582 + indirect inscattering in
583 + .I mist
584 + is accounted for by volume photons. Contribution photons are treated as
585 + global photons by
586 + .I rpict.
587 + .IP
588 + Additionally specifying
589 + .I bwidth2
590 + enables bias compensation for the density estimates with a
591 + minimum and maximum bandwidth of
592 + .I bwidth1
593 + and
594 + .I bwidth2,
595 + respectively.
596 + .IP
597 + Global photon irradiance may be optionally precomputed by
598 + .I mkpmap(1),
599 + in which case the bandwidth, if specified, is ignored, as the nearest photon
600 + is invariably looked up.
601 + .IP
602 + Using direct photons replaces the direct calculation with density estimates
603 + for debugging and validation of photon emission.
604 + .TP
605 + .BI -am " frac"
606 + Maximum search radius for photon map lookups.  Without this option, an
607 + initial maximum search radius is estimated for each photon map from the
608 + average photon distance to the distribution's centre of gravity.  It is then
609 + adapted to the photon density in subsequent lookups.  This option imposes a
610 + global fixed maximum search radius for
611 + .I all
612 + photon maps, thus defeating the automatic adaptation.  It is useful when
613 + multiple warnings about short photon lookups are issued.  Note that this
614 + option does not conflict with the bandwidth specified with the
615 + .I \-ap
616 + option; the number of photons found will not exceed the latter, but may be
617 + lower if the maximum search radius contains fewer photons, thus resulting in
618 + short lookups.  Setting this radius too large, on the other hand, may
619 + degrade performance.
620 + .TP
621 + .BI -ac " pagesize"
622 + Set the photon cache page size when using out-of-core photon mapping. The
623 + photon cache reduces disk I/O incurred by on-demand loading (paging) of
624 + photons, and thus increases performance. This
625 + is expressed as a (float) multiple of the density estimate bandwidth
626 + specified with
627 + .I \-ap
628 + under the assumption that photon lookups are local to a cache page. Cache
629 + performance is sensitive to this parameter: larger pagesizes will reduce the
630 + paging frequency at the expense of higher latency when paging does occur.
631 + Sensible values are in the range 4 (default) to 16.
632 + .TP
633 + .BI -aC " cachesize"
634 + Set the total number of photons cached when using out-of-core photon
635 + mapping, taking into account the pagesize specified by
636 + .I \-ac.
637 + Note that this is approximate as the number of cache pages is rounded to
638 + the nearest prime. This allows adapting the cache to the available physical
639 + memory. Cache performance is less sensitive to this parameter, and reasonable
640 + performance can obtained with as few as 10k photons. The default is 1M. This
641 + option recognises multiplier suffixes (k = 1e3, M = 1e6), both in upper and
642 + lower case.
643 + .TP
644   .BI -me " rext gext bext"
645   Set the global medium extinction coefficient to the indicated color,
646   in units of 1/distance (distance in world coordinates).
# Line 535 | Line 687 | though the
687   .I \-dv
688   option (above) may be used to override this.
689   .TP
690 + .BR \-u
691 + Boolean switch to control uncorrelated random sampling.
692 + When "off", a low-discrepancy sequence is used, which reduces
693 + variance but can result in a dithered appearance in specular highlights.
694 + When "on", pure Monte Carlo sampling is used in all calculations.
695 + .TP
696   .BI -lr \ N
697   Limit reflections to a maximum of
698 < .I N.
698 > .I N,
699 > if N is a positive integer.
700 > If
701 > .I N
702 > is zero, then Russian roulette is used for ray
703 > termination, and the
704 > .I -lw
705 > setting (below) must be positive.
706 > If N is a negative integer, then this limits the maximum
707 > number of reflections even with Russian roulette.
708 > In scenes with dielectrics and total internal reflection,
709 > a setting of 0 (no limit) may cause a stack overflow.
710   .TP
711   .BI -lw \ frac
712   Limit the weight of each ray to a minimum of
713   .I frac.
714 < During ray-tracing, a record is kept of the final contribution
715 < a ray would have to the image.
716 < If it is less then the specified minimum, the ray is not traced.
714 > During ray-tracing, a record is kept of the estimated contribution
715 > (weight) a ray would have in the image.
716 > If this weight is less than the specified minimum and the
717 > .I -lr
718 > setting (above) is positive, the ray is not traced.
719 > Otherwise, Russian roulette is used to
720 > continue rays with a probability equal to the ray weight
721 > divided by the given
722 > .I frac.
723   .TP
724 + .BI -cs \ Ns
725 + Use
726 + .I Ns
727 + bands for spectral sampling rather than the default RGB calculation space.
728 + The maximum setting is controlled by the compiler macro MAXCSAMP, and
729 + defaults to 24.
730 + Larger values for Ns will be reduced to MAXCSAMP.
731 + .TP
732 + .BI -cw " nmA nmB"
733 + Set extrema to the given wavelengths for spectral sampling.
734 + The default is 380 and 780 nanometers.
735 + The order specified does not matter.
736 + .TP
737   .BI -S \ seqstart
738   Instead of generating a single picture based only on the view
739   parameters given on the command line, this option causes
# Line 732 | Line 920 | Set the time between progress reports to
920   A progress report writes the number of rays traced, the percentage
921   completed, and the CPU usage to the standard error.
922   Reports are given either automatically after the specified interval,
923 < or when the process receives a continue (-CONT) signal (see
923 > or when the process receives a continue (\-CONT) signal (see
924   .I kill(1)).
925   A value of zero turns automatic reporting off.
926   .TP
# Line 740 | Line 928 | A value of zero turns automatic reporting off.
928   Send error messages and progress reports to
929   .I efile
930   instead of the standard error.
931 + (Note this option overlaps with "-e expr" above, so file paths
932 + with '=' or ':' in them are not allowed on this option.)
933   .TP
934   .BR \-w
935   Boolean switch for warning messages.
936   The default is to print warnings, so the first appearance of
937   this option turns them off.
938   .SH EXAMPLE
939 < rpict -vp 10 5 3 -vd 1 -.5 0 scene.oct > scene.pic
939 > rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.hdr
940   .PP
941 < rpict -S 1 -o frame%02d.pic scene.oct < keyframes.vf
941 > rpict \-S 1 \-o frame%02d.hdr scene.oct < keyframes.vf
942 > .PP
943 > To render ambient irradiance in photon mapping mode from a global photon
944 > map global.pm via one ambient bounce, and from a caustic photon map
945 > caustic.pm:
946 > .IP "" .2i
947 > rpict -ab 1 -ap global.pm 50 -ap caustic.pm 50 -vf scene.vf scene.oct >
948 > scene.hdr
949   .SH ENVIRONMENT
950   RAYPATH         the directories to check for auxiliary files.
951   .SH FILES
952 < /usr/tmp/rtXXXXXX               common header information for picture sequence
952 > /tmp/rtXXXXXX           common header information for picture sequence
953   .br
954   rfXXXXXX                temporary name for recover file
955   .SH DIAGNOSTICS
# Line 768 | Line 965 | option.
965   .SH AUTHOR
966   Greg Ward
967   .SH "SEE ALSO"
968 < getinfo(1), lookamb(1), oconv(1), pfilt(1), pinterp(1), pmblur(1),
969 < printf(3), ra_rgbe(1), rad(1), rtrace(1), rview(1)
968 > getinfo(1), lookamb(1), mkpmap(1), oconv(1), pdfblur(1), pfilt(1),
969 > pinterp(1), pmblur(1), printf(3), ra_rgbe(1), rad(1), rpiece(1), rtpict(1), rtrace(1), rvu(1), rxpiece(1)

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