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