ies2rad
Radiance ies2rad program
IES2RAD(1) IES2RAD(1)
NAME
ies2rad - convert IES luminaire data to RADIANCE description
SYNOPSIS
ies2rad [ options ] [ input .. ]
DESCRIPTION
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. (Note, this means that the IES "width"
is actually along the Y axis, while "length" corresponds to 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 direc-
tory 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 color-balanced renderings. In general, it is impor-
tant 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 envi-
ronment variable. The default is the current working direc-
tory.
-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 com-
mand 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 fol-
lowed 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.
EXAMPLE
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
ENVIRONMENT
RAYPATH directories to search for lamp lookup table
AUTHOR
Greg Ward
BUGS
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 assign-
ing colors to fixtures is less than perfect, and the IES would do well
to include explicit spectral information somehow in their specifica-
tion.
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 rectangu-
lar, 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 lumi-
naire geometry as MGF data, though nothing in the standard requires
manufacturers to provide this information.
SEE ALSO
mgf2rad(1), oconv(1), pfilt(1), rad2mgf(1), rpict(1), xform(1)
RADIANCE 6/14/96 IES2RAD(1)
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– last modified
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