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       genskyvec - compute patch radiance averages for a specific sky


       genskyvec [ -m N ][ -c r g b ]


       Genskyvec  samples  the  Radinace sky description given on the standard
       input to generate a list of average patch radiances.  If there is a sun
       in  the  description,  genskyvec  will  include its contribution in the
       three nearest sky patches, distributing energy  according  to  centroid

       By default, genskyvec divides the sky into 2305 patches, plus one patch
       for the ground.   This  corresponds  to  Reinhart’s  extension  of  the
       Tregenza  sky,  where  the  original 145 patches are subdivided into 16
       subpatches, except at the  zenith.   A  different  subdivision  may  be
       specified via the -m option.  The value given will be used to subdivide
       each dimension, so the default of 4 yields  almost  16  times  as  many
       patches as the original Tregenza sky, which can be specified with -m 1.
       A higher resolution sky is generally better  for  daylight  coefficient
       analysis where solar position is important.

       The  -c  option  may  be used to specify a color for the sky.  The gray
       value should equal 1 for proper energy balance The default sky color is
       -c 0.960 1.004 1.118 .


       To  generate  578  patches  corresponding  to  a 2x2 subdivision of the
       Tregenza sky on a sunny equinox noon:

         gensky 9 21 12 | genskyvec -m 2 > sky09_21_12.dat


       Greg Ward


       dctimestep(1), gensky(1), gentregvec(1), rtcontrib(1), rtrace(1)