NAME

       genklemsamp - generate ray samples over surfaces using Klems BSDF basis

SYNOPSIS

       genklemsamp [ -c N ][ -f{a|f|d} ] [ view opts ] [ geom.rad ..  ]

DESCRIPTION

       Genklemsamp  generates  ray  origins  and  directions  to sample planar surfaces needed to
       determine incident radiances or daylight coefficients.  This command is typically used  in
       conjunction  with  rtcontrib(1)  to  analyze  exterior daylight coefficients for an annual
       simulation.

       The view options are needed to specify (at minimum) the view direction, which  corresponds
       to  the  orientation  of  the  surfaces,  and the view up vector, which corresponds to the
       azimuth=90-degree position on the Klems  sampling  hemisphere.   The  view  fore  clipping
       distance  is also quite useful, as it provides a means to pass through some thickness in a
       fenestration system before samples are sent out.  Other view options such as the view type
       and aft clipping distance are overridden or ignored.

       If  no  Radiance  scene  files  are provided, then the specified parallel view defines the
       width, height, center, and orientation of the window or facade of  interest.   If  one  or
       more  scene  files  are  given,  they  are  presumed to contain planar surfaces over which
       genklemsamp will originate samples.  The sampled surface normals must  correspond  to  the
       specified view direction, and unaligned surfaces are silently ignored.

       The  -c  option specifies the number of rays to sample per Klems direction.  These samples
       will be distributed evenly over the surface(s).  The default setting is 1000.

       The -ff option specifies that output rays should be generated as 32-bit IEEE binary  float
       values.   This may be more efficient if passed directly to rtcontrib or rtrace(1) with the
       same option.  Likewise, the -fd option specifies 64-bit IEEE binary  double  values.   The
       default setting of -fa produces ASCII floating point values.

EXAMPLE

       To  generate  500  samples  per  direction  over a set of south-facing windows and pass to
       rtcontrib to compute daylight coefficients in a matrix:

         genklemsamp -c 500 -vd 0 -1 0 -vu 0 0 1 south_windows.rad | rtcontrib -c 500 -e MF:1  -f
         reinhart.cal -b rbin -bn Nrbins exterior.oct > Dsouth.dat

AUTHOR

       Greg Ward

SEE ALSO

       dctimestep(1), genBSDF(1), genskyvec(1), mkillum(1), rtcontrib(1), rtrace(1), vwrays(1)