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.\" RCSid $Id: dctimestep.1,v 1.2 2010/07/01 21:54:55 greg Exp $" |
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.TH DCTIMESTEP 1 12/09/09 RADIANCE |
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.SH NAME |
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dctimestep - compute annual simulation time-step via matrix multiplication |
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.SH SYNOPSIS |
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.B dctimestep |
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.B DCspec |
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[ |
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.B skyvec |
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] |
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.br |
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.B dctimestep |
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.B Vspec |
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.B Tbsdf.xml |
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.B Dmat.dat |
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[ |
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.B skyvec |
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] |
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.SH DESCRIPTION |
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.I Dctimestep |
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has two invocation forms. |
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In the first form, |
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.I dctimestep |
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is given a daylight coefficient specification and an optional sky |
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vector, which may be read from the standard input if unspecified. |
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The daylight coefficients are multiplied against this vector and the results |
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are written to the standard output. |
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This may be a list of color values or a combined Radiance image, |
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as explained below. |
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.PP |
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In the second form, |
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.I dctimestep |
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takes four input files, forming a matrix expression. |
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The first argument is the View matrix file that specifies how window output |
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directions are related to some set of measured values, such as an array of |
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illuminance points or images. |
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This matrix is usually computed by |
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.I rcontrib(1) |
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for a particular set of windows or skylight openings. |
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The second argument is the window transmission matrix, or BSDF, given as |
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a standard XML description. |
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The third argument is the Daylight matrix file that defines how sky patches |
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relate to input directions on the same opening. |
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This is usually computed using |
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.I genklemsamp(1) |
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with |
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.I rcontrib |
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in a separate run for each window or skylight orientation. |
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The final input is the sky contribution vector, |
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usually computed by |
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.I genskyvec(1), |
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which may be passed on the standard input. |
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This data must be in ASCII format, whereas the View and Daylight matrices |
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are more efficiently represented as binary float data if machine |
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byte-order is not an issue. |
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.PP |
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Sent to the standard output of |
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.I dctimestep |
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is either an ASCII color vector with as many RGB triplets |
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as there are rows in the View matrix, or a combined |
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.I Radiance |
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picture. |
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Which output is produced depends on the first argument. |
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A regular file name will be loaded and interpreted as a matrix to |
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generate a color results vector. |
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A file specification containing a '%d' format string will be |
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interpreted as a list of |
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.I Radiance |
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component pictures, which will be summed according to the computed |
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vector. |
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.SH EXAMPLES |
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To compute workplane illuminances at 3:30pm on Feb 10th: |
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.IP "" .2i |
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gensky 2 10 15:30 | genskyvec | dctimestep workplaneDC.dmx > Ill_02-10-1530.dat |
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.PP |
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To compute an image at 10am on the equinox from a set of component images: |
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.IP "" .2i |
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gensky 3 21 10 | genskyvec | dctimestep viewc%03d.hdr > view_03-21-10.hdr |
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.PP |
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To compute a set of illuminance contributions for Window 1 on |
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the Winter solstice at 2pm: |
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.IP "" .2i |
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gensky 12 21 14 | genskyvec | dctimestep IllPts.vmx Blinds20.xml Window1.dmx > Ill_12-21-14.dat |
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.PP |
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To compute Window2's contribution to an interior view at 12 noon on the Summer solstice: |
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.IP "" .2i |
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gensky 6 21 12 | genskyvec | dctimestep view%03d.hdr Blinds30.xml Window2.dmx > view_6-21-12.hdr |
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.SH AUTHOR |
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Greg Ward |
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.SH "SEE ALSO" |
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genklemsamp(1), genskyvec(1), mkillum(1), rcontrib(1), rtrace(1), vwrays(1) |
