Radiance genskyvec program

GENSKYVEC(1)                                                      GENSKYVEC(1)

NAME

       genskyvec - compute patch radiance averages for a specific sky

SYNOPSIS

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

DESCRIPTION

       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
       proximity.

       By default, genskyvec divides the sky into 2305 patches, plus one patch
       for the ground.  This corresponds to Reinhart's extension of  the  Tre-
       genza  sky,  where the original 145 patches are subdivided into 16 sub-
       patches, except at the zenith.  A different subdivision may  be  speci-
       fied 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 .

EXAMPLE

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

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

AUTHOR

       Greg Ward

SEE ALSO

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

RADIANCE                           12/09/09                       GENSKYVEC(1)