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Comparing ray/doc/man/man1/rtcontrib.1 (file contents):
Revision 1.2 by greg, Thu May 26 18:53:04 2005 UTC vs.
Revision 1.14 by greg, Tue Oct 11 16:54:26 2005 UTC

#	Line 1 | Line 1
1		.\" RCSid "$Id$"
2	<	.TH RPIECE 1 5/25/05 RADIANCE
2	>	.TH RTCONTRIB 1 5/25/05 RADIANCE
3		.SH NAME
4	<	rtcontrib - compute contributions in a RADIANCE scene
4	>	rtcontrib - compute contribution coefficients in a RADIANCE scene
5		.SH SYNOPSIS
6		.B rtcontrib
7		[
8		.B "\-n nprocs"
9		][
10	+	.B \-fo
11	+	|
12	+	.B \-r
13	+	][
14		.B "\-e expr"
15		][
16		.B "\-f source"
17		][
18	<	.B "\-o fspec"
18	>	.B "\-o ospec"
19		][
20		.B "\-b binv"
21	+	][
22	+	.B "\-bn nbins"
23		]
24	<	.B "\-m mod .."
24	>	{
25	>	.B "\-m mod | \-M file"
26	>	}
27	>	..
28		[
29		.B $EVAR
30		]
#	Line 26 | Line 35 | rtcontrib - compute contributions in a RADIANCE scene
35		rtrace options
36		]
37		.B octree
38	+	.br
39	+	.B "rtcontrib [ options ] \-defaults"
40		.SH DESCRIPTION
41		.I Rtcontrib
42		computes ray contributions (i.e., color coefficients)
#	Line 35 | Line 46 | settings.
46		These modifiers are usually materials associated with
47		light sources or sky domes, and must directly modify some geometric
48		primitives to be considered in the output.
49	<	The computed contributions can then be used in linear combination to
49	>	A modifier list may also be read from a file using the
50	>	.I \-M
51	>	option.
52	>	The RAYPATH environment variable determines directories to search for
53	>	this file.
54	>	(No search takes place if a file name begins with a '.', '/' or '~'
55	>	character.)\0
56	>	.PP
57	>	The output of
58	>	.I rtcontrib
59	>	has many potential uses.
60	>	Source contributions can be used as components in linear combination to
61		reproduce any desired variation, e.g., simulating lighting controls or
62		changing sky conditions via daylight coefficients.
63		More generally,
64		.I rtcontrib
65	<	may be used to compute input-output relationships in optical
66	<	systems, such as light pipes and shading devices.
65	>	can be used to compute arbitrary input-output relationships in optical
66	>	systems, such as luminaires, light pipes, and shading devices.
67		.PP
68		.I Rtcontrib
69		calls
70		.I rtrace(1)
71	<	to calculate the contributions for each input ray,
72	<	and the output tallies are sent to one or more files according to the
71	>	with the -oTW option to calculate the daughter ray
72	>	contributions for each input ray, and the output tallies
73	>	are sent to one or more destinations according to the given
74		.I \-o
75		specification.
76	+	If a destination begins with an exclamation mark ('!'), then
77	+	a pipe is opened to a command and data is sent to its standard input.
78	+	Otherwise, the destination is treated as a file.
79	+	An existing file of the same name will not be clobbered, unless the
80	+	.I \-fo
81	+	option is given.
82	+	If instead the
83	+	.I \-r
84	+	option is specified, data recovery is attempted on existing files.
85		If an output specification contains a "%s" format, this will be
86		replaced by the modifier name.
87		The
#	Line 58 | Line 90 | option may be used to further define
90		a "bin number" within each object if finer resolution is needed, and
91		this will be applied to a "%d" format in the output file
92		specification if present.
93	<	(The actual bin number is computed at run time based on ray direction
94	<	and surface intersection, as described below.)\0
93	>	The actual bin number is computed at run time based on ray direction
94	>	and surface intersection, as described below.
95	>	If the number of bins is known in advance, it should be specified with the
96	>	.I \-bn
97	>	option, and this is critical for output files containing multiple values
98	>	per record.
99	>	Since bin numbers start from 0, the bin count is always equal to
100	>	the last bin plus 1.
101	>	Set the this value to 0 if the bin count is unknown (the default).
102		The most recent
103	<	.I \-b
103	>	.I \-b,
104	>	.I \-bn
105		and
106		.I \-o
107		options to the left of each
#	Line 80 | Line 120 | the variables Px, Py, and Pz, and the normalized ray d
120		will be assigned to Dx, Dy, and Dz.
121		These parameters may be combined with definitions given in
122		.I \-e
123	<	options and files read in
123	>	arguments and files read using the
124		.I \-f
125	<	options, to compute the bin, which will be
125	>	option.
126	>	The computed bin value will be
127		rounded to the nearest whole number.
128		This mechanism allows the user to define precise regions or directions
129		they wish to accumulate, such as the Tregenza sky discretization,
130		which would be otherwise impossible to specify
131		as a set of RADIANCE primitives.
132	+	The rules and predefined functions available for these expressions are
133	+	described in the
134	+	.I rcalc(1)
135	+	man page.
136	+	Unlike
137	+	.I rcalc,
138	+	.I rtcontrib
139	+	will search the RADIANCE library directories for each file given in a
140	+	.I \-f
141	+	option.
142		.PP
143		If no
144		.I \-o
145		specification is given, results are written on the standard output in order
146		of modifier (as given on the command line) then bin number.
147	<	Concatenated data is also sent to a lone output file (i.e., an initial
147	>	Concatenated data is also sent to a single destination (i.e., an initial
148		.I \-o
149		specification without formatting strings).
150		If a "%s" format appears but no "%d" in the
#	Line 168 | Line 219 | pcomb -c 100 90 75 c_light1.pic -c 50 55 57 c_light2.p
219		.PP
220		To compute an array of illuminance contributions according to a Tregenza sky:
221		.IP "" .2i
222	<	rtcontrib -b tbin -o sky.dat -m skyglow -b 0 -o ground.dat -m groundglow
222	>	rtcontrib -I+ -b tbin -o sky.dat -m skyglow -b 0 -o ground.dat -m groundglow
223		@render.opt -f tregenza.cal scene.oct < test.dat
224	+	.SH ENVIRONMENT
225	+	RAYPATH         path to search for -f and -M files
226		.SH AUTHOR
227		Greg Ward
228		.SH "SEE ALSO"

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