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ies2rad - convert IES luminaire data to RADIANCE description
ies2rad [ options ] [ input .. ]
Ies2rad converts one or more IES luminaire data files to the
equivalent RADIANCE scene description. The light source
geometry will always be centered at the origin aimed in the
negative z direction, with the 0 degree plane along the x
axis. Usually, two output files will be created for every
input file, one scene file (with a ".rad" suffix) and one
data file (with a ".dat" suffix). If the IES input file
includes tilt data, then another data file will be created
(with a "+.dat" suffix). If the -s option is used, the
scene data will be sent to the standard output instead of
being written to a file. Since the data file does not
change with other options to ies2rad, this is a convenient
way to specify different lamp colors and multipliers inline
in a scene description. If the -g option is used, then an
octree file will be created (with the ".oct" suffix). The
root portion of the output file names will be the same as
the corresponding input file, unless the -o option is used.
The output files will be created in the current directory
(no matter which directory the input files came from) unless
the -l or -p options are used.
Ies2rad assigns light source colors based on information in
a lamp lookup table. Since most lamps are distinctly
colored, it is often desirable to override this lookup
procedure and use a neutral value that will produced colorbalanced
renderings. In general, it is important to
consider lamp color when an odd assortment of fixture types
is being used to illuminate the same scene, and the
rendering can always be balanced by pfilt(1) to a specific
white value later.
- -l libdir Set the library directory path to libdir. This is
-
where all relative pathnames will begin for output
file names. For light sources that will be used
by many people, this should be set to some central
location included in the RAYPATH environment
variable. The default is the current working
directory.
- -p prefdir
-
Set the library subdirectory path to prefdir. This
is the subdirectory from the library where all
output files will be placed. It is often most
convenient to use a subdirectory for the storage
of light sources, since there tend to be many
files and placing them all in one directory is
very messy. The default value is the empty
string.
- -o outname
-
Set the output file name root to outname. This
overrides the default output file name root which
is the same as the input file. This option may be
used for only one input file, and is required when
reading data from the standard input.
- -s
- Send the scene information to the standard output
rather than a separate file. This is appropriate
when calling ies2rad from within a scene
description via an inline command. The data
file(s) will still be written based on the output
file name root, but since this information is
unaffected by command line options, it is safe to
have multiple invocations of ies2rad using the
same input file and different output options. The
-s option may be used for only one input file.
- -dunits
- Output dimensions are in units, which is one of
the letters `m', `c', `f', or `i' for meters,
centimeters, feet or inches, respectively. The
letter specification may be followed by a slash
('/') and an optional divisor. For example,
-dm/1000 would be millimeters. The default output
is in meters, regardless of the original units in
the IES input file. Note that there is no space
in this option.
- -i rad
- Ignore the crude geometry given by the IES input
file and use instead an illum sphere with radius
rad. This option may be useful when the user
wishes to add a more accurate geometric
description to the light source model, though this
need is obviated by the recent LM-63-1995
specification, which uses MGF detail geometry.
(See -g option below.)
- -g
- If the IES file contains MGF detail geometry,
compile this geometry into a separate octree and
create a single instance referencing it instead of
including the converted geometry directly in the
Radiance output file. This can result in a
considerable memory savings for luminaires which
are later duplicated many times in a scene, though
the appearance may suffer for certain luminaires
since the enclosed glow sources will not light the
local geometry as they would otherwise.
- -f lampdat
-
Use lampdat instead of the default lamp lookup
table (lamp.tab) to map lamp names to xy
chromaticity and lumen depreciation data. It is
often helpful to have customized lookup tables for
specific manufacturers and applications.
- -t lamp
- Use the given lamp type for all input files.
Normally, ies2rad looks at the header lines of the
IES file to try and determine what lamp is being
used in the fixture. If any of the lines is
matched by a pattern in the lamp lookup table (see
the -f option above), that color and depreciation
factor will be used instead of the default (see
the -c and -u options). The lamp specification is
also looked up in the lamp table unless it is set
to "default", in which case the default color is
used instead.
- -c red grn blu
-
Use the given color if the type of the lamp is
unknown or the -t option is set to "default". If
unspecified, the default color will be white.
- -u lamp
- Set the default lamp color according to the entry
for lamp in the lookup table (see the -f option).
This is the color that will be used if the input
specification does not match any lamp type
patterns. This option is used instead of the -c
option.
- -m factor Multiply all output quantities by factor. This is
-
the best way to scale fixture brightness for
different lamps, but care should be taken when
this option is applied to multiple files.
To convert a single IES data file in inches with color
balanced output and 15% lumen depreciation, creating the
files "fluor01.rad" and "fluor01.dat" in the current
directory:
ies2rad -di -t default -m .85 fluor01.ies
To convert three IES files of various types to tenths of a
foot and put them in the library "/usr/local/lib/ray"
subdirectory "source/ies":
ies2rad -df/10 -l /usr/local/lib/ray -p source/ies ies01
ies02 ies03
To convert a single file and give the output a different
name:
ies2rad -o fluorescent ies03
- RAYPATH
- directories to search for lamp lookup table
Greg Ward
In pre-1991 standard IES files, all header lines will be
examined for a lamp table string match. In post-1991
standard files, only those lamps with the [LAMP] or
[LAMPCAT] keywords will be searched. The first match found
in the file is always the one used. This method of
assigning colors to fixtures is less than perfect, and the
IES would do well to include explicit spectral information
somehow in their specification.
The IESNA LM-63 specification prior to 1995 provided three
basic source shapes, rectangular, round, and elliptical.
The details of these shapes is vague at best. Rectangular
sources will always be rectangular, but ies2rad will
approximate round sources as spherical if the height is
close to or greater than the width and length, and as a ring
otherwise. Elliptical sources are treated the same as round
sources. The 1995 standard rectifies this problem by
including detailed luminaire geometry as MGF data, though
nothing in the standard requires manufacturers to provide
this information.
mgf2rad(1), oconv(1), pfilt(1), rad2mgf(1), rpict(1),
xform(1)
Header and Footer
IES2RAD(1) RADIANCE (6/14/96) IES2RAD(1)
Page 1 (printed 7/17/96)
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