man/man1/genskyvec.1

.\" RCSid $Id: genskyvec.1,v 1.7 2023/12/06 01:27:00 greg Exp $
.TH GENSKYVEC 1 12/09/09 RADIANCE
.SH NAME
genskyvec - compute patch radiance averages for a specific sky
.SH SYNOPSIS
.B genskyvec
[
.B "\-h"
][
.B "\-m N"
][
.B "\-c r g b"
][
.B "\-d"
]
.SH DESCRIPTION
.I Genskyvec
samples the
.I Radinace
sky description given on the standard input to generate a list of
average patch radiances.
If there is a sun in the description,
.I genskyvec
will include its contribution in the three nearest sky patches,
distributing energy according to centroid proximity.
.PP
By default,
.I genskyvec
divides the sky into 2305 patches, plus one patch for the ground.
This corresponds to Reinhart's extension of the Tregenza sky,
where the original 145 patches are subdivided into 16 subpatches,
except at the zenith.
A different subdivision may be specified via the
.I \-m
option.
The value given will be used to subdivide each dimension, so the
default of 4 yields almost 16 times as many patches
as the original Tregenza sky, which can be specified with
.I "\-m 1."
A higher resolution sky is generally better for daylight
coefficient analysis where solar position is important.
.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
The default sky color is
.I "\-c 0.960 1.004 1.118".
.PP
The
.I \-d
option may be used to produce a sun-only vector, with no sky contributions.
If a time of day is selected or sky type that has no sun, then a zero vector
is produced.
.PP
Normally, a header will be produced containing the number of rows and other
information required by
.I dctimestep(1).
The
.I \-h
option may be used to elide this information header, producing data values only.
.SH EXAMPLE
To generate 578 patches corresponding to a 2x2 subdivision of the
Tregenza sky on a sunny equinox noon:
.IP "" .2i
gensky 9 21 12 | genskyvec -m 2 > sky09_21_12.dat
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
dctimestep(1), genBSDF(1), gendaylit(1),
gendaymtx(1), gensky(1), rcollate(1), rcomb(1),
rcontrib(1), rmtxop(1), rtrace(1)
Revision:	1.8
Committed:	Tue Dec 12 16:31:45 2023 UTC (16 months, 3 weeks ago) by greg
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.7:	+3 -3 lines
Log Message:	chore(rcomb): Renamed rmtxcomb to simpler "rcomb"
#	Content
1	.\" RCSid $Id: genskyvec.1,v 1.7 2023/12/06 01:27:00 greg Exp $
2	.TH GENSKYVEC 1 12/09/09 RADIANCE
3	.SH NAME
4	genskyvec - compute patch radiance averages for a specific sky
5	.SH SYNOPSIS
6	.B genskyvec
7	[
8	.B "\-h"
9	][
10	.B "\-m N"
11	][
12	.B "\-c r g b"
13	][
14	.B "\-d"
15	]
16	.SH DESCRIPTION
17	.I Genskyvec
18	samples the
19	.I Radinace
20	sky description given on the standard input to generate a list of
21	average patch radiances.
22	If there is a sun in the description,
23	.I genskyvec
24	will include its contribution in the three nearest sky patches,
25	distributing energy according to centroid proximity.
26	.PP
27	By default,
28	.I genskyvec
29	divides the sky into 2305 patches, plus one patch for the ground.
30	This corresponds to Reinhart's extension of the Tregenza sky,
31	where the original 145 patches are subdivided into 16 subpatches,
32	except at the zenith.
33	A different subdivision may be specified via the
34	.I \-m
35	option.
36	The value given will be used to subdivide each dimension, so the
37	default of 4 yields almost 16 times as many patches
38	as the original Tregenza sky, which can be specified with
39	.I "\-m 1."
40	A higher resolution sky is generally better for daylight
41	coefficient analysis where solar position is important.
42	.PP
43	The
44	.I \-c
45	option may be used to specify a color for the sky.
46	The gray value should equal 1 for proper energy balance
47	The default sky color is
48	.I "\-c 0.960 1.004 1.118".
49	.PP
50	The
51	.I \-d
52	option may be used to produce a sun-only vector, with no sky contributions.
53	If a time of day is selected or sky type that has no sun, then a zero vector
54	is produced.
55	.PP
56	Normally, a header will be produced containing the number of rows and other
57	information required by
58	.I dctimestep(1).
59	The
60	.I \-h
61	option may be used to elide this information header, producing data values only.
62	.SH EXAMPLE
63	To generate 578 patches corresponding to a 2x2 subdivision of the
64	Tregenza sky on a sunny equinox noon:
65	.IP "" .2i
66	gensky 9 21 12 \| genskyvec -m 2 > sky09_21_12.dat
67	.SH AUTHOR
68	Greg Ward
69	.SH "SEE ALSO"
70	dctimestep(1), genBSDF(1), gendaylit(1),
71	gendaymtx(1), gensky(1), rcollate(1), rcomb(1),
72	rcontrib(1), rmtxop(1), rtrace(1)