[ViewVC] Diff of: Development/ray/doc/man/man1/rtrace.1

Comparing ray/doc/man/man1/rtrace.1 (file contents):
Revision 1.24 by greg, Thu Nov 15 19:41:03 2012 UTC vs.
Revision 1.33 by greg, Thu Jul 4 01:07:25 2019 UTC

+ascii, 'f' for single-precision floating point,
+and 'd' for double-precision floating point.
+In addition to these three choices, the character 'c' may be used
-<
+to denote 4-byte floating point (Radiance) color format
-<
+for the output of values only
-<
+.I (\-ov
-<
+option, below).
->
+to denote 4-byte RGBE (Radiance) color format
->
+for the output of individual color values only, and the
->
+.I \-x
->
+and
->
+.I \-y
->
+options should also be specified to create a valid output picture.
+If the output character is missing, the input format is used.
+.IP
+Note that there is no space between this option and its argument.
+.IP
+M       material name
+.IP
-+
+r       mirrored value contribution
-+
+.IP
-+
+x       unmirrored value contribution
-+
+.IP
-+
+R       mirrored ray length
-+
+.IP
-+
+X       unmirrored ray length
-+
+.IP
+~       tilde (end of trace marker)
+.IP
+If the letter 't' appears in
+.TP
+.BR -bv
+Boolean switch for back face visibility.
-<
+With this switch off, back faces of opaque objects will be invisible
-<
+to all rays.
->
+With this switch off, back faces of all objects will be invisible
->
+to view rays.
+This is dangerous unless the model was constructed such that
-<
+all surface normals on opaque objects face outward.
->
+all surface normals face outward.
+Although turning off back face visibility does not save much
+computation time under most circumstances, it may be useful as a
+tool for scene debugging, or for seeing through one-sided walls from
+the outside.
-–
+This option has no effect on transparent or translucent materials.
+.TP
+.BI -av " red grn blu"
+Set the ambient value to a radiance of
+.BI -ab \ N
+Set the number of ambient bounces to
+.I N.
-<
+This is the maximum number of diffuse bounces
-<
+computed by the indirect calculation.
-<
+A value of zero implies no indirect calculation.
->
+This is the maximum number of diffuse bounces computed by the indirect
->
+calculation. A value of zero implies no indirect calculation.
->
+.IP
->
+This value defaults to 1 in photon mapping mode (see
->
+.I -ap
->
+below), implying that global photon irradiance is always computed via
->
+.I one
->
+ambient bounce; this behaviour applies to any positive number of ambient
->
+bounces, regardless of the actual value specified.  A negative value enables
->
+a preview mode that directly visualises the irradiance from the global
->
+photon map without any ambient bounces.
+.TP
+.BI -ar \ res
+Set the ambient resolution to
+except read modifiers to be included from
+.I file.
+.TP
-+
+.BI -ap " file [bwidth1 [bwidth2]]"
-+
+Enable photon mapping mode. Loads a photon map generated with
-+
+.I mkpmap(1)
-+
+from
-+
+.I file,
-+
+and evaluates the indirect irradiance depending on the photon type
-+
+(automagically detected) using density estimates with a bandwidth of
-+
+.I bwidth1
-+
+photons, or the default bandwidth if none is specified (a warning will be
-+
+issued in this case).
-+
+.IP
-+
+Global photon irradiance is evaluated as part of the ambient calculation (see
-+
+.I \-ab
-+
+above), caustic photon irradiance is evaluated at primary rays, and
-+
+indirect inscattering in
-+
+.I mist
-+
+is accounted for by volume photons. Contribution photons are treated as
-+
+global photons by
-+
+.I rtrace.
-+
+.IP
-+
+Additionally specifying
-+
+.I bwidth2
-+
+enables bias compensation for the density estimates with a
-+
+minimum and maximum bandwidth of
-+
+.I bwidth1
-+
+and
-+
+.I bwidth2,
-+
+respectively.
-+
+.IP
-+
+Global photon irradiance may be optionally precomputed by
-+
+.I mkpmap(1),
-+
+in which case the bandwidth, if specified, is ignored, as the nearest photon
-+
+is invariably looked up.
-+
+.IP
-+
+Using direct photons replaces the direct calculation with density estimates
-+
+for debugging and validation of photon emission.
-+
+.TP
-+
+.BI -am " frac"
-+
+Maximum search radius for photon map lookups.  Without this option, an
-+
+initial maximum search radius is estimated for each photon map from the
-+
+average photon distance to the distribution's centre of gravity.  It is then
-+
+adapted to the photon density in subsequent lookups.  This option imposes a
-+
+global fixed maximum search radius for
-+
+.I all
-+
+photon maps, thus defeating the automatic adaptation.  It is useful when
-+
+multiple warnings about short photon lookups are issued.  Note that this
-+
+option does not conflict with the bandwidth specified with the
-+
+.I \-ap
-+
+option; the number of photons found will not exceed the latter, but may be
-+
+lower if the maximum search radius contains fewer photons, thus resulting in
-+
+short lookups.  Setting this radius too large, on the other hand, may
-+
+degrade performance.
-+
+.TP
-+
+.BI -ac " pagesize"
-+
+Set the photon cache page size when using out-of-core photon mapping. The
-+
+photon cache reduces disk I/O incurred by on-demand loading (paging) of
-+
+photons, and thus increases performance. This
-+
+is expressed as a (float) multiple of the density estimate bandwidth
-+
+specified with
-+
+.I \-ap
-+
+under the assumption that photon lookups are local to a cache page. Cache
-+
+performance is sensitive to this parameter: larger pagesizes will reduce the
-+
+paging frequency at the expense of higher latency when paging does occur.
-+
+Sensible values are in the range 4 (default) to 16.
-+
+.TP
-+
+.BI -aC " cachesize"
-+
+Set the total number of photons cached when using out-of-core photon
-+
+mapping, taking into account the pagesize specified by
-+
+.I \-ac.
-+
+Note that this is approximate as the number of cache pages is rounded to
-+
+the nearest prime. This allows adapting the cache to the available physical
-+
+memory. In conjunction with the
-+
+.I \-n
-+
+option, this is the cache size
-+
+.I per parallel process.
-+
+Cache performance is less sensitive to this parameter,
-+
+and reasonable performance can obtained with as few as 10k photons. The
-+
+default is 1M. This option recognises multiplier suffixes (k = 1e3, M =
-+
+e6), both in upper and lower case.
-+
+.TP
+.BI -me " rext gext bext"
+Set the global medium extinction coefficient to the indicated color,
+in units of 1/distance (distance in world coordinates).
+termination, and the
+.I -lw
+setting (below) must be positive.
-<
+If N is a negative integer, then this sets the upper limit
-<
+of reflections past which Russian roulette will be used.
->
+If N is a negative integer, then this limits the maximum
->
+number of reflections even with Russian roulette.
+In scenes with dielectrics and total internal reflection,
+a setting of 0 (no limit) may cause a stack overflow.
+.TP
+on most multiprocessing platforms, since the
+.I fork(2)
+system call will share memory on a copy-on-write basis.
-+
+.SH NOTES
-+
+Photons are generally surface bound (an exception are volume photons), thus
-+
+the ambient irradiance in photon mapping mode will be biased at positions
-+
+which do not lie on a surface.
+.SH EXAMPLES
+To compute radiance values for the rays listed in samples.inp:
+.IP "" .2i
+.IP "" .2i
+cnt 480 640 | rcalc \-e 'xr:640;yr:480' \-f unusual_view.cal | rtrace
+\-x 640 \-y 480 \-fac scene.oct > unusual.hdr
-+
+.PP
-+
+To compute ambient illuminance in photon mapping mode from a global photon
-+
+map global.pm via one ambient bounce, and from a caustic photon map
-+
+caustic.pm at sensor positions in samples.inp:
-+
+.IP "" .2i
-+
+rtrace -h -ov -ab 1 -ap global.pm 50 -ap caustic.pm 50 scene.oct <
-+
+samples.inp > illum.out
+.SH ENVIRONMENT
+RAYPATH         the directories to check for auxiliary files.
+.SH FILES
+.SH AUTHOR
+Greg Ward
+.SH "SEE ALSO"
-<
+getinfo(1), lookamb(1), oconv(1), pfilt(1), pinterp(1),
-<
+pvalue(1), rpict(1), rcontrib(1), rvu(1), vwrays(1), ximage(1)
->
+getinfo(1), lookamb(1), mkpmap(1), oconv(1), pfilt(1), pinterp(1),
->
+pvalue(1), rcontrib(1), rpict(1), rtpict(1), rvu(1), vwrays(1), ximage(1)

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Comparing ray/doc/man/man1/rtrace.1 (file contents): Revision 1.24 by greg, Thu Nov 15 19:41:03 2012 UTC vs. Revision 1.33 by greg, Thu Jul 4 01:07:25 2019 UTC

Diff Legend

Comparing ray/doc/man/man1/rtrace.1 (file contents):
Revision 1.24 by greg, Thu Nov 15 19:41:03 2012 UTC vs.
Revision 1.33 by greg, Thu Jul 4 01:07:25 2019 UTC