Ubuntu Manpage: ies2rad - convert IES luminaire data to RADIANCE description

Provided by: radiance_4R1+20120125-1.1_amd64

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 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 color-balanced 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.

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/share/radiance" subdirectory "source/ies":

         ies2rad -df/10 -l /usr/share/radiance -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 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.