--- ray/doc/man/man1/gendaymtx.1	2014/06/17 18:03:48	1.7
+++ ray/doc/man/man1/gendaymtx.1	2021/02/17 02:30:08	1.15
@@ -1,4 +1,4 @@
-.\" RCSid $Id: gendaymtx.1,v 1.7 2014/06/17 18:03:48 greg Exp $
+.\" RCSid $Id: gendaymtx.1,v 1.15 2021/02/17 02:30:08 greg Exp $
 .TH GENDAYMTX 1 01/19/13 RADIANCE
 .SH NAME
 gendaymtx - generate an annual Perez sky matrix from a weather tape
@@ -9,8 +9,16 @@ gendaymtx - generate an annual Perez sky matrix from a
 ][
 .B "\-h"
 ][
-.B "\-d|\-s"
+.B "\-A"
 ][
+.B "\-d|\-s|\-n"
+][
+.B "\-u"
+][
+.B "\-D sunfile"
+[
+.B "\-M sunmods"
+]][
 .B "\-r deg"
 ][
 .B "\-m N"
@@ -42,7 +50,7 @@ parameter setting.
 .PP
 Increasing the
 .I \-m
-parameter, typically by factors of two, yields a higher resolution
+parameter yields a higher resolution
 sky using the Reinhart patch subdivision.
 For example, setting
 .I "\-m 4"
@@ -53,6 +61,14 @@ Thus, an hourly weather tape for an entire year would
 yield 8760x3 (26280) values per output line (row).
 .PP
 The
+.I \-A
+option tells
+.I gendaymtx
+to generate a single column corresponding to an average sky
+computed over all the input time steps, rather than one
+column per time step.
+.PP
+The
 .I \-c
 option may be used to specify a color for the sky.
 The gray value should equal 1 for proper energy balance.
@@ -67,11 +83,58 @@ corresponding to a 20% gray.
 .PP
 The
 .I \-d
-option may be used to produce a sun-only matrix, with no sky contributions.
+option may be used to produce a sun-only matrix, with no sky contributions,
+and the ground patch also set to zero.
 Alternatively, the
 .I \-s
-option may be used to exclude any direct solar component from the output.
+option may be used to exclude any direct solar component from the output,
+with the rest of the sky and ground patch unaffected.
+If there is a sun in the description,
+.I gendaymtx
+will include its contribution in the four nearest sky patches,
+distributing energy according to centroid proximity.
 .PP
+The
+.I \-u
+option ignores input times when the sun is below the horizon.
+This is a convenient way to average daylight hours only with the
+.I \-A
+option or to ensure that matrix entries correspond to solar positions
+produced with the
+.I \-D
+option, described below.
+.PP
+The
+.I \-n
+option may be used if no matrix output is desired at all.
+This may be used to merely check the input, or in combination with the
+.I \-D
+option, below.
+.PP
+The
+.I \-D
+option may be used to specify an output file to contain a list of
+solar positions and intensities corresponding to time steps in the
+weather tape where the sun has any portion above the horizon.
+Sun radiance values may be zero if the direct amount is zero on the input.
+Sun modifiers and names will be indexed by the minute, numbered from
+midnight, January 1st.
+If a hyphen ('-') is given as the argument to
+.I \-D,
+then the sun descriptions  will be directed to the standard output.
+This implies the
+.I \-n
+option just described.
+If the
+.I \-M
+option is given as well, it will be used to record the modifier
+names used in the
+.I \-D
+output, for convenient input to
+.I rcontrib(1)
+and
+.I rfluxmtx(1).
+.PP
 By default,
 .I gendaymtx
 assumes the positive Y-axis points north such that the first sky patch
@@ -128,4 +191,4 @@ based on Jean-Jacques Delaunay's original gendaylit(1)
 Greg Ward wrote the final parameter parsing and weather tape conversion.
 .SH "SEE ALSO"
 dctimestep(1), genBSDF(1), gendaylit(1), gensky(1), genskyvec(1),
-rcollate(1), rcontrib(1), xform(1)
+rcollate(1), rcontrib(1), rfluxmtx(1), xform(1)