--- ray/doc/notes/ReleaseNotes	2004/09/10 16:05:07	1.43
+++ ray/doc/notes/ReleaseNotes	2014/02/08 01:28:05	1.231
@@ -1140,7 +1140,7 @@ of recursive routines using sets to avoid overrunning
 the stack limit.
 
 ==============================
-Version 3.6
+Version 3.6 (Released 10/21/04)
 
 Modified 4-byte RGBE encoding routine to avoid problems
 when one or two primary values is negative and the other(s)
@@ -1256,7 +1256,7 @@ Added -I option to replmarks for mesh instancing.
 Made similar change for virtual sources to allow modifiers and aliases
 on the mirror and prism types to work properly.
 
-Rob Guglielmetti dded -lw and -lh options to falsecolor to control the
+Rob Guglielmetti added -lw and -lh options to falsecolor to control the
 legend dimensions.  Made it so -lw 0 and/or -lh 0 turns legend off.
 
 Made it so pcompos will read everything from a stream even if it doesn't
@@ -1296,7 +1296,7 @@ Fixed a very obscure bug in rpict that caused a dark h
 line in certain cylindrical projections due to improper drawing
 of the sky dome source in rt/srcdraw.c.
 
-Fixed problems with effective ray lenths computed for dielectric
+Fixed problems with effective ray lengths computed for dielectric
 and BRTDfunc materials.  This was most evident in breakup of holodeck
 views when VDISTANCE=True.
 
@@ -1305,3 +1305,622 @@ Fixed rad so that 'scene' variable may consist only of
 Fixed bug introduced in shadow caching routines where sources in the
 middle of spheres were not illuminating properly.  Thanks to Guilio
 Antonutto for spotting this problem.
+
+Modified gensky behavior so if time is given with standard time zone
+designation, any -m option is ignored.
+
+Added -n option to mkillum for (shared memory) parallel processing.
+
+Fixed a long-standing bug in parallel processing code that only
+seemed to manifest with the new mkillum -n option, where rtrace
+would deadlock upon termination.  The reason it never showed up
+before is because I always closed processes in the reverse order
+of opening them in other programs.  I went through and found similar
+(potential) bugs in the rview device subprocess code and util/netproc.c.
+
+Corrected the normalization of the Gaussian reflectance model.  This will
+cause an increase in specularity for low-lying light sources.
+Thanks to Don Walters of Boeing and Arne Duer of the Univ. of Innsbruck
+for pointing out this error.  The square root used for the two cosines
+in the denominator of the normalization factor should not be present.
+This was a serious mistake I made in the original model, which went
+undiscovered (at least to my knowledge) for over a decade.  I think
+Bruce Walter of Cornell may have known about it, but I never heard
+the details of his discovery.
+
+Enabled the -p option for primary conversion without tone-mapping
+in ra_bmp.  Also provides for XYZE input conversion to RGB.
+
+Fixed what I consider a bug in pvalue -o when taking XYZE files on input,
+where it was inappropriately undoing the exposure value so that it always
+reported radiance rather than XYZ values with Y in cd/m^2.
+
+Made it so ra_bmp only produces run-length encoded 8-bit output for
+grayscale images that are tone-mapped.  This minimizes circumstances
+under which output scanline order is reversed.
+
+Fixed bug in rcalc where it sometimes wasn't parsing the input format
+correctly.
+
+=====================
+Version 3.7 (Released 7/25/05)
+
+Fixed bug in source occluder cache which caused consistency error
+for distant sources and mist materials.  (Thanks to Mark Stock for
+finding the problem.)
+
+Fixed serious bug in source drawing routines for rpict, where the edges
+of light sources were appearing through obstructions.  (Thanks to Veronica
+Sundstedt for pointing this out.)
+
+(The above were included in the 3.6.1 patch release.)
+
+Changed default temporary directory from /usr/tmp, which doesn't exist
+on a lot of systems these days, to /tmp.
+
+Eliminated many unused files and programs from the distribution, including
+the following programs that were being built but no longer used:
+	oki20	- printer driver for OkiMate 20 printer (B&W)
+	oki20c	- printer driver for OkiMate 20 color printer
+	pcwarp	- intended as more general substitute for macbetcal,
+			but never quite worked
+	ra_avs	- convert to & from AVS image format
+	ra_bn	- convert to & from Barneyscann format
+	ra_pr	- convert to & from 8-bit Sun rasterfile format
+	ra_pr24	- convert to & from 24-bit Sun rasterfile format
+	thf2rad	- convert GDS "things file" to Radiance scene format
+If anyone is still wanting any of the above programs, let us know and we'll
+reinstate it.
+
+Fixed bug in pcond's acuity simulation for small view angles (less than
+4 degrees horizontally or vertically).  Thanks to James Lee for figuring
+this out.
+
+Added script to convert to/from ICT's Poskanzer Float Map, which I don't
+care to support officially due to its machine-dependent byte order.
+
+Fixed bug that caused incorrect reporting of non-surface in set when
+mixing meshes and instances.  (Thanks to Jack de Valpine for discovery.)
+
+Fixed inaccuracy in calculation of diffuse transmission in the presence
+of pure specular (Fresnel reflection) using "trans" material.  Thanks
+to Christoph Reinhart for pointing out the error.
+
+Made internal change to tone-mapping library to use structure pointer
+rather than stack, making code re-entrant and more up to modern standards.
+
+Added -pd option to handle depth-of-field blur in rpict.  This requires
+that the view directon (-vd option) include focal distance information,
+which is now preserved by the various view file routines, and reported
+by the vwright command.
+
+Added DBLUR variable to ranimate and pmdblur script to handle simultaneous
+motion and depth-of-field blurring.  Thanks to Visarc for funding this work.
+
+Added setting of focus distance in rvu ("focus" command) and rholo
+('f'/"frame" command).
+
+Changed default remote shell in ranimate to "ssh" rather than "rsh",
+which has been abandoned on most Unix systems due to security issues.
+
+Fixed behavior of source primitive using illum with no alternate
+material.  These now become transparent so one can see the sky or
+light-probe background for use in image-based lighting.  Previously,
+the user needed to specify the background glow as the alternate
+material for a distant illum source to behave properly.  (This still
+works.)
+
+Fixed some minor problems and inconsistencies with 16-bit/channel
+TIFF i/o in ra_tiff.
+
+Created mksource program to generate distant sources for improved
+image-based lighting with light probes.
+
+Changed ambient calculation so that -ad will not limit recursion
+depth, and a minimum of 27 samples will be sent out for each stored
+ambient value, or 3 samples if -aa is 0 (caching off).
+
+Added -oM option to rtrace to report material (rather than modifier)
+for cases where actual material is aliased or further up modifier chain.
+
+Rearranged the way ray contributions are computed so that it might be
+possible to use rtrace to derive daylight coefficients and optical
+transfer functions.  The new -oTW option of rtrace produces color
+contribution weights for each ray, which combined with the -ti (or -tI)
+option permits the contribution of selected surfaces or sources to
+be determined.  Using the -oTW option, one should also specify
+options "-dt 0 -aa 0 -as 0" for optimal results.  In particular,
+one cannot expect reasonable tallies with -ab >= 1 and irradiance
+caching on (-aa > 0).
+
+The same code modifications included a change to the indirect computation
+with caching switched off (-aa 0).  Whereas before, the number of secondary
+rays after the first bounce were half of the previous generation, they are
+now determined by the surface reflectance, making for a better and faster
+calculation.  It should now be possible to compute many bounces with -aa 0,
+which used to be prohibitively expensive.
+
+Added -T option to xshowtrace to trace rays to light sources.
+
+Added meta2bmp program to produce BMP files from metafile graphics.
+
+Added cct_x(t) and cct_y(t) to src/cal/cal/blackbody.cal to interpolate
+CIE chromaticities for particular black-body temperatures.
+
+Increased maximum number of input pictures in pcomb and pcompos to 512.
+
+Created rtcontrib program for computing ray contribution coefficients.
+This tool may be used to do standard optical ray tracing or daylight
+coefficient calculations for annual simulations, among other uses.
+
+Added tilde ('~') output option as part of the -o* specification of
+rtrace.  This permits ray trees to be parsed more easily in binary
+output mode, as needed by rtcontrib.
+
+Implemented Russian roulette ray termination with -lr <= 0.
+Made -lr -10 the default in rtcontrib.
+
+Made rtcontrib -f option search RAYPATH directories.
+
+Made it so -o option of rtcontrib can pipe -o output to a command.
+
+Added -if and -of options to total for binary i/o (following rcalc mold).
+
+Switched default options in rtrace to use Russian roulette.  (Rpict and rvu
+still use biased ray termination.)
+
+Added rtcontrib -r option to recover partial output.
+
+Added -u rendering option for pure Monte Carlo sampling.
+(Got rid of -DMC compile option, which this makes superfluous.)
+
+Changed -t option of rlam to accept strings as well as single characters.
+
+Fixed bug in rcalc with -l option where it would sometimes go into an
+infinite loop.
+
+Fixed truly ancient bug in bounding box computation for cones, which
+could (and did) cause missing segments.
+
+Added -z option to normtiff to output LZW-compressed files.
+
+Last change to total causes it to produce results when it sees an empty
+line on the input.  This was not intentional, but I decided I like this
+behavior so I documented it rather than changing it.
+
+=====================
+Version 3.8 (Released 10/17/06)
+
+Fixed Russian roulette ray termination, which was doing the opposite of
+what it should have been doing, resulting in overestimated values below
+minimum ray sampling weight (serious).
+
+Changed mksource to use 98th percentile (rather than 99th) for threshold.
+
+(Above changes included in 3.7.1 patch release.)
+
+Eliminated writing of EXPOSURE= line in ra_tiff -r when source TIFF
+does not have STONITS set.
+
+Fixed bug in ambient calculation that caused black values for multiple
+bounces in some scenes.  Thanks to Mark Stock for creating and sharing
+the sophisticated test scene that demonstrated this problem.
+
+Fixed bug in antimatter using Russian Roulette sampling.
+
+(Above changes included in 3.7.2 patch release 22 Aug 2005.)
+
+Created fieldcomb script to combine alternate fields in a rendering
+sequence.  (Development generously sponsored by Iebele Abel.)
+
+Added missing preload of mesh objects for more efficient memory use
+during parallel rendering -- this was a serious oversight.
+
+Created ran2tiff program to automate exposure setting of animation
+sequences using a moving histogram in combination with pcond, and
+converting frames to TIFF.
+
+Eliminated SPEED macro from makeall and source tree.
+
+Added -pj option to vwrays to allow jittering of sample locations.
+
+Fixed bug in rtcontrib where it occasionally missed writing the
+final bin file.  (Pretty serious, actually.)
+
+Added -Dfseeko=fseek to MACH= line for linux, as fseeko(3) seems to be
+broken in current versions of Linux.  (Need to remove this later.)
+
+Rearranged struct's for better efficiency on 64-bit architectures.
+
+Added -i option to rlam so it works with binary input formats.
+
+Added rtcontrib -bn option to specify number of bins and fixed bug
+in recovery of files containing multiple values per record.
+
+Added rtcontrib -fo option to write over existing files, which it now
+refuses to do without this option.
+
+Made rtcontrib flush output when handed a zero-length ray vector,
+to match behavior of rtrace.
+
+Improved color scale for falsecolor output.
+
+Added threshold test for Fresnel approximation to prevent its use
+on smooth surfaces with unrealistically low specularities (less than 1.8%).
+Water has a specular reflectance of 2.1% at room temperture.
+
+Removed NICE macro settings in rpict and rtrace, which was slowing down
+the processes under Mac OS X (10.4) by about 60% due to processor napping.
+
+Made xform, replmarks and rad2mgf handle quoted modifiers and names properly.
+
+Fixed problem in genblinds, where it was generating slats that were too
+wide with the +/-r option.  (Thanks to Helena Buelow-Huebe for discovering
+this bug.)
+
+Fixed bug in ra_ppm for 16-bit/sample i/o, where it was getting the byte
+order wrong (apparently).
+
+Added -V option to rtcontrib to report actual contributions, rather than
+just ray coefficients.
+
+Fixed bug in ranimate that caused it to fail in continuation of renderings.
+
+Renamed librt.a to librtrad.a, to avoid conflict on Solaris. Almost
+everything now gets linked to -lrtrad instead of -lrt.
+
+Fixed problem with large sample sets, so -u+ option now is truly random.
+Thanks to Rick Mistrick and Younju Yoon for identifying this problem,
+which was related to a poorly designed hash function.
+
+Changed -u+ to be the default setting in rtrace (only).
+
+Fixed binary i/o for rlam and vwrays under Windows.
+
+Added tmCvLums() to tone-mapping routines using a 16-bit lookup table
+on IEEE floats, which is also used to improve speed of COLOR conversions,
+especially on machines with slow log() calls.  The first call to
+tmCvLums(), tmCvGrays(), or tmCvColors() initializes the table.
+
+Created optics2rad.csh script to convert from Optics 5 material output
+to something correct for Radiance.  Built on old glazing.cal function,
+which is actually incorrect so removed from the distribution.
+
+Fixed nuisance bug in ximage under some SGI machines that caused it to
+choose an inappropriate visual and display incorrect colors.  (Thanks
+to Oskar Itzinger for debugging the problem.)
+
+Fixed long-standing inaccuracy of pcompos -t and +t thresholding options.
+
+Fixed bug in handling of views with tabs rather than spaces.
+
+Fixed bug related to alias of alias.
+
+****** COMPATIBILITY CHANGE ********
+Changed default sky turbidity in gensky from the original default of
+2.75 to the CIE 110-1994 standard value of 2.45.  Thanks to Marilyne
+Anderson of MIT for pointing out this discrepancy.
+
+Added -o option to ra_xyze to produce original pixel values.
+
+Fixed bug in tracing of virtual sources, where intervening glazing was
+not being accounted for properly.
+
+Added -h option to pcompos and pcomb to eliminate verbose headers.
+
+=====================
+Version 3.9 (Released 3/30/08)
+
+Added -spec option to falsecolor to restore original spectral color scale.
+Also added "-s auto" option to automatically set the maximum value.
+
+Added byte-swapping input and output to rcalc.
+
+Additional error-checking for source surfaces.
+
+Re-fixed bug in octree code that caused it to allocate 8 times as
+much memory as it actually used(!) -- this was pointed out way back
+in 1999 by Erik Reinhard and Erik Jansen, but the fix they gave me
+got lost in the slightly broken release process at the time.  This
+should make a big difference in memory usage, especially for the
+new mesh primitive.  (I measured 30% less memory usage.)
+
+Corrected ray weights for material mixtures.
+
+Reduced the default -n setting for obj2mesh to take better advantage
+of the smaller octree structure size.
+
+Fixed bug in shadow cache where it was adding surfaces with antimatter
+holes cut in them to the obstructor list.  Thanks to John Mardaljevic
+for discovering and reporting the problem.
+
+Adding ability in mkillum to incorporate BSDF data in calculation.
+Internal interface (raypcalls) now used in place of rtrace process(es).
+
+Fixed pixel alignment in pcomb for size reduction and enlargement.
+
+Allow rtcontrib user to set -P and -PP options for persistent rendering.
+The only caveat is that -n setting > 1 requires -PP rather than -P.
+
+Added -c option to rtcontrib to facilitate cumulative calculations.
+
+****** COMPATIBILITY CHANGE ********
+Fixed long-standing bug in source.cal, which caused it to produce
+reversed anisotropic photometric distributions due to the
+misorientation of the y-axis.  Thanks to Zack Rogers for discovering
+and helping debug this problem.
+
+Fixed long-standing bug in replmarks, where triangles with X-side
+aligned with Z-axis would cause incorrect rotations.  Thanks to
+Zack Rogers for finding this error.
+
+Added rsensor program to compute sensor signal for daylighting controls.
+Funding for this component was provided by the Architectural Energy
+Corporation in Boulder, CO, and directed by Zack Rogers.
+
+Added "planisphere" (stereographic) fisheye view type for traditional
+daylighting analysis.  Feature requested & explained by Axel Jacobs.
+
+Modified -c option to rtcontrib so it can take a number of input
+rays to average over, rather than only produce a single accumulated
+record (which can now be done with -c 0).
+
+=====================
+Version 4.0 (Released 3/12/10)
+
+Added -n option to rvu to provide parallel rendering.
+
+****** COMPATIBILITY CHANGE ********
+Changed ".pic" extension to ".hdr" in all sources and documentation
+to improve interoperability with other software, since this has become
+the de facto extension for Radiance RGBE and XYZE pictures.  Since file
+extensions were never more than a convention in Radiance, this does not
+affect operation, but may require the update of scripts, etc. written
+by others that assume the ".pic" suffix for Radiance output.
+
+Added -N option to objview to support multiprocessing.
+
+Improved sampling of circular sources (source, sphere, ring types) with
+quite a bit of help from David Geisler-Moroder.
+
+Added "rpict" and "rvu" variables to rad, and made these as well as
+the "oconv", "mkillum" and "pfilt" variables accept an alternate
+command path in each case.  Change suggested by Lars Grobe based
+on similar Radzilla (radz) facility by Carsten Bauer.
+
+Fixed rad -v N specification to use actual view name if one.
+
+Fixed error in mkillum calculation where it neglected indirect
+source contributions from BTDF illum's.
+
+Added GMT and LATLONG header lines for Greenwich Mean Time and
+degrees North Latitude / East Longitude.
+
+Added gendaylit to distribution (finally).
+
+Added ability in vwright(1) to get view from command line arguments.
+
+Created genklemsamp(1) utility to generate samples suitable for
+BSDF-based annual calculations.  This is the first Perl script to
+be added to Radiance.  Hopefully, others will follow.
+
+Added klems_int.cal file to compute Klems bins for windows.
+
+Created genskyvec  utility to sample a particular sky and
+evaluate average radiance over the standard Tregenza sky patches.
+
+Created dctimestep program to compute a set of sensor values or
+a combined image for a particular time using the daylight
+coefficient method.
+
+Created src/rt/rayfifo.c for first-in/first-out handling of
+multiprocessing by raypcalls.c.
+
+Added -n option to rtrace for executing on multiple cores
+using new rayfifo calls.
+
+=====================
+Version 4.1 (Released 11/04/2011)
+
+Changed ranimate behavior so remote login under a different user
+doesn't necessarily require the presence of the originating user's
+home directory.
+
+Changed standard transmission function normalization back to what
+it was in version 3.5, following recommendation of David Geisler-Moroder,
+who pointed out that the revised BTDF increased too much at grazing.
+
+Changed rad behavior with -N >1 on single view to call rpiece.
+
+Updated SCons build system for MINGW compilation, thanks to Christian
+Kohler.
+
+Added -u option to rlam for unbuffered output.
+
+Modified dctimestep to accept sky vector and daylight coefficient matrix
+or list of images to sum together, as suggested by Andy McNeil.
+
+Created genBSDF script to generate BSDF in Windows XML format.
+
+Modified mkillum to accept detailed geometry from BSDF XML files.
+
+Altered obj2rad to ignore zero normals (thanks to Jack de Valpine for
+suggestions and help).
+
+Fixed bug in genklemsamp that caused non-uniform sampling over surfaces.
+
+Fixed bugs in rhoptimize and rhcopy for 64-bit compilation.
+
+Made a change to avoid problem using gcc --fast-math compile option.
+
+****** COMPATIBILITY CHANGE ********
+Changed behavior of rtrace and rtcontrib so that every scanline is
+not flushed when both -x and -y are set.  This avoids flush delays
+in rtcontrib for large numbers of output files and delays while
+rendering images using rtrace with the -n option.
+
+Added ability for rsensor to output ray origins and directions
+rather than actually loading octree and computing sensor value.
+
+Fixed old bug in obj2rad where it would stop processing and
+report a syntax error if the "void" type is used in the map file.
+
+Updated reflection model according to EGSR 2010 paper by David
+Geisler-Moroder and Arne Duer.
+
+Replaced C-shell version of falsecolor with Perl script written
+by Axel Jacobs.
+
+****** COMPATIBILITY CHANGE ********
+Changed -sj (specular jitter) option to something called specular
+sampling (-ss), which if set less than 1 has the same behavior as
+the old -sj, but when set greater than 1, spawns multiple ray
+samples from semi-specular surfaces.
+
+Fixed bug noticed by Randolph Fritz that caused ambient sync errors.
+
+Fixed bug in findglare for reading picture files under Windows.
+
+Added options to pvalue to note other color spaces on reverse conversion.
+Thanks to Erich Philips for the feature request.
+
+Added BSDF data-driven material type with full sampling support.
+
+Added BRDF calculations to genBSDF.
+
+Bug fixes in rsensor thanks to help from David Geisler-Moroder.
+
+Added variable-resolution BSDF support in renderers and genBSDF.
+
+Created pkgBSDF program to extract BSDF geometry and put it
+together with surface description suitable for inclusion in
+a Radiance scene.
+
+Muted warning for "no light sources found" when there is at least
+one glow object and interreflections are on (-ab > 0).
+
+Fixed long-standing bug that caused underestimation of reflection
+when specular component was below -st threshold in non-metals.
+
+Checked in cross-platform cmake build system created by Bill Hoffman
+of KitWare and sponsored by NREL.  This includes a qt-based
+driver for rvu, which is built in the new subdirectory src/qtrvu.
+
+=====================
+Version 4.2
+
+Axel Jacobs added -cp and -palettes options to falsecolor.
+
+Fixed bug in matrix output of genBSDF introduced shortly before 4.1 release.
+
+Made rvu more responsive in multi-processing mode when changing parameters.
+Explicit "new" command not needed to show changes, because it goes back
+to "immediate mode" once something is changed.  Processing will be slow
+but response time quick until next "new" command.
+
+Fixed major bug in transmitting proxy material sampling.
+
+Patched cmake build tools (changes by Zack Galbreath).
+
+Removed requirement for pflip -h to be given input file (can pipe from stdin).
+
+Added "Number of processes" slider to trad "Action" pane to control rad -N
+option for rvu and batch rendering.
+
+Added -c option to vwrays to repeat pixels for rtcontrib.
+
+Reworked rtcontrib program and renamed to rcontrib.  New version runs much
+faster, especially on multiprocessor systems, and doesn't require as much
+memory.  No longer calls rtrace; instead does all the work itself.
+
+Added -d option to genskyvec to produce direct-only (sun no sky) vector.
+
+Added Ashikhmin-Shirley anisotropic BRDF model (ashik2) with help
+from Nicolas Boneel.
+
+Added Ruby rewrite of objview.csh by Rob Guglielmetti.
+
+Fixed bug in reciprocity for tensor tree BTDF representations.  Thanks
+to Andy McNeil for identifying the problem.
+
+Added MNAME and ZNAME variables to ranimove for debugging & testing.
+
+Created pmblur2 command to take motion and depth buffers from ranimove
+to compute a better motion blur.
+
+****** COMPATIBILITY CHANGE ********
+Changed BSDF routines to use updated/corrected XML specification and
+removed depracated BSDF support from mkillum.
+
+Fixed behavior of i/o flushing in rcontrib with -c > 1 (averaging).  Thanks
+to Lars Grobe for help identifying this problem.
+
+Fixed bug in depth-of-field blur where view distance was measured from
+fore clipping plane rather than viewpoint.  Thanks to Peter A-B for
+pointing this out.
+
+Added options to dctimestep to allow multiple time steps (-n)
+and multiple output pictures or sensor files (-o).  Also added -i
+option to specify float (-if) or double (-id) input for sky matrix.
+
+Created gendaymtx program to compute annual sky patch matrix based
+on Ian Ashdown's implementation of Perez all-weather sky model.
+Output can be sent directly to dctimestep in ASCII or binary stream.
+
+Replaced existing gendaylit.c with improved version from Wendelin Sprenger
+and Jan Wienold of ISE.
+
+Improved accuracy of ambient calculation for large -ad settings.  Thanks
+to Lars Grobe for noticing the problem.
+
+Added -r option to gendaymtx to rotate the sky the specified number of
+degrees about the zenith as suggested by A. McNeil.
+
+Axel Jacobs added -pal eco color map that does a blue-red-yellow scale.
+
+Created bsdf2klems tool to convert from various BSDF representations to
+Klems basis matrix in XML file.
+
+Fixed problem with inappropriate reciprocity enforcement on tensor
+tree reduction in genBSDF.  (Thanks to A.McNeil for discovering issue.)
+
+Fixed bug in isotropic tensor tree sampling for impinging rays
+exactly normal to surface.  Thanks to Peter Apian-Bennewitz for
+discovering and pointing out the error.
+
+Fixed double-counting bug in mirror material with alternate type.
+Thanks to David Geisler-Moroder for spotting the problem and helping
+to fix it.
+
+Created rcollate program to resize and transpose matrix data for Andy
+McNeil's 5-phase annual simulation method.
+
+Added epw2wea conversion program by Christoph Reinhart.
+
+Implemented Perlin's improved noise function with help from Rahul Narain.
+This will change the appearance of renderings using this function.
+
+Added "origin" command to rvu as requested by John Mardaljevic
+to place view origin at selected point in scene.
+
+Switch to Perl versions of objview and objpict written by Axel Jacobs.
+
+Improved rendering speed of scenes with aliases by not entering new
+modifiers into table if they are the same as the previously defined
+modifier for that name.
+
+Made it so icalc and rcalc search RAYPATH directories for *.cal files
+given on command line.  This simplifies script writing and makes these
+utilities consistent with other tools in Radiance.
+
+Added triangulation routine to handle convex polygons in obj2mesh.
+
+****** COMPATIBILITY CHANGE ********
+Made backface visibility apply to all material types, including
+transparent and translucent materials (except dielectric and interface).
+This makes the option useful in cases where adjacent trans surfaces
+are placed next to each other by a modeler that only understands
+volumetric objects.
+
+Changed dctimestep so that output matrices (-n > 1) are preceded by a
+header, and added support for float and double output formats with -o[fd].