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.\" RCSid $Id$ |
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.TH GENSKYVEC 1 12/09/09 RADIANCE |
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.SH NAME |
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genskyvec - compute patch radiance averages for a specific sky |
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.SH SYNOPSIS |
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.B genskyvec |
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[ |
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.B "\-m N" |
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][ |
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.B "\-c r g b" |
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] |
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.SH DESCRIPTION |
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.I Genskyvec |
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samples the |
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.I Radinace |
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sky description given on the standard input to generate a list of |
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average patch radiances. |
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If there is a sun in the description, |
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.I genskyvec |
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will include its contribution in the three nearest sky patches, |
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distributing energy according to centroid proximity. |
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.PP |
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By default, |
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.I genskyvec |
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divides the sky into 2305 patches, plus one patch for the ground. |
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This corresponds to Reinhart's extension of the Tregenza sky, |
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where the original 145 patches are subdivided into 16 subpatches, |
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except at the zenith. |
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A different subdivision may be specified via the |
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.I \-m |
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option. |
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The value given will be used to subdivide each dimension, so the |
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default of 4 yields almost 16 times as many patches |
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as the original Tregenza sky, which can be specified with |
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.I "\-m 1." |
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A higher resolution sky is generally better for daylight |
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coefficient analysis where solar position is important. |
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.PP |
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The |
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.I \-c |
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option may be used to specify a color for the sky. |
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The gray value should equal 1 for proper energy balance |
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The default sky color is |
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.I "\-c 0.960 1.004 1.118". |
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.SH EXAMPLE |
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To generate 578 patches corresponding to a 2x2 subdivision of the |
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Tregenza sky on a sunny equinox noon: |
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.IP "" .2i |
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gensky 9 21 12 | genskyvec -m 2 > sky09_21_12.dat |
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.SH AUTHOR |
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Greg Ward |
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.SH "SEE ALSO" |
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dctimestep(1), gensky(1), gentregvec(1), rtcontrib(1), rtrace(1) |
