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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.  (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

       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

       -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
                 (  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

       -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


       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


       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

       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)