man/man1/rfluxmtx.1

.\" RCSid "$Id: mkillum.1,v 1.12 2013/08/11 02:57:49 greg Exp $"
.TH RFLUXMTX 1 07/22/14 RADIANCE
.SH NAME
rfluxmtx - compute flux transfer matrix(es) for RADIANCE scene
.SH SYNOPSIS
.B rfluxmtx
[
.B \-v
][
.B "rcontrib options"
]
.B "{ sender.rad | - }"
.B receivers.rad
.B "[ scene.rad .. ]"
.SH DESCRIPTION
.I Rfluxmtx
samples rays uniformly over the surface given in
.I sender.rad
and records rays arriving at surfaces in the file
.I receivers.rad,
producing a flux transfer matrix per receiver.
Additional scene surfaces are given in optional
.I scene.rad
files, which are compiled with the receivers into an octree sent to the
.I rcontrib(1)
program to do the actual work.
If a single hyphen ('-') is given in place of the sender file, then
.I rfluxmtx
passes ray samples from its standard input directly to
.I rcontrib
without interpretation.
By default, all resulting matrix data are interleaved and sent to the standard output
in ASCII format, but this behavior is typically overridden using inline options
as described below.
.PP
The
.I \-v
option turns on verbose reporting for the number of samples and the executed
.I rcontrib
command.
All other supported options are passed on to
.I rcontrib(1).
However, the
.I \-f,
.I \-e,
.I \-p,
.I \-b,
.I \-bn,
.I \-m,
and
.I \-M
options are controlled by
.I rfluxmtx
and may not be set by the user.
Also, the
.I \-x,
.I \-y,
and
.I \-ld
options are ignored unless
.I rfluxmtx
is invoked in the pass-through mode,
in which case they may be needed to generate RADIANCE views from
.I vwrays(1).
The sample count, unless set by the
.I \-c
option, defaults to 10000 when a sender file is given, and 1 for pass-through mode.
.SH VARIABLES
The sender and receiver scene files given to
.I rfluxmtx
contain controlling parameters in specal comments of the form:
.nf

        #@rfluxmtx variable=value ..

.fi
At minimum, both sender and receiver must specify one of the
hemisphere sampling types, and there must be at least
one surface in each file.
.TP 10n
.BI h =u
Set hemisphere sampling to "uniform," meaning a single bin
of (cosine-distributed) samples.
In the case of distant "source" primatives, this is the only
sampling method that supports arbitrary receiver sizes.
The other methods below require a full hemispherical source.
.TP
.BI h =kf
Divide the hemisphere using the LBNL/Klems "full" sampling basis.
.TP
.BI h =kh
Divide the hemisphere using the LBNL/Klems "half" sampling basis.
.TP
.BI h =kq
Divide the hemisphere using the LBNL/Klems "quarter" sampling basis.
.TP
.BI h =rN
Divide the hemisphere using Reinhart's substructuring of the Tregenza
sky pattern with
.I N
divisions in each dimension.
If it is not given,
.I N
defaults to 1, which is just the Tregenza sky.
.TP
.BI h =scN
Subdivide the hemisphere using the Shirley-Chiu square-to-disk mapping with an
.I NxN
grid over the square.
.TP
.BI u =[-]{X|Y|Z|ux,uy,uz}
Orient the "up" direction for the hemisphere using the indicated axis or direction
vector.
.TP
.BI o =output.mtx
Send the matrix data for this receiver to the indicated output file.
The file format will be determined by the command-line
.I \-fio
option and will include an information header unless the
.I \-h
option was used to turn headers off.
(The output file specification is ignored for senders.)\0
.PP
In normal execution, only a single sender surface is sampled, but it may be
comprised of any number of subsurfaces, as in a triangle mesh or similar.
The surface normal will be computed as the average of all the constituent
subsurfaces.
The subsurfaces themselves must be planer, thus only
.I polygon
and
.I ring
surface primitives are supported.
Other primitives will be silently ignored and will have no effect on the calculation.
.PP
In the receiver file, the
.I source
primitive is supported as well, and multiple receivers (and multiple output
matrices) are identified by different modifier names.
Though it may be counter-intuitive, receivers are often light sources,
since samples end up there in a backwards ray-tracing system such as RADIANCE.
.PP
Rays always eminate from the back side of the sender surface and arrive at the
front side of receiver surfaces.
In this way, a receiver surface may be reused as a sender in a subsequent
.I rfluxmtx
calculation and the resulting matrices will concatenate properly.
(Note that it is important to keep receiver surfaces together, otherwise a
"duplicate modifier" error will result.)\0
.SH EXAMPLES
To generate a flux transfer matrix connecting input and output apertures
on a light pipe:
.IP "" .3i
rcontrib int_aperture.rad ext_aperture.rad lpipe.rad > lpipe.mtx
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
genBSDF(1), getinfo(1), rcalc(1), rcollate(1), rcontrib(1), rmtxop(1), vwrays(1)
Revision:	1.1
Committed:	Tue Jul 22 21:55:31 2014 UTC (10 years, 9 months ago) by greg
Branch:	MAIN
Log Message:	Created man page for rfluxmtx and added some error checks
#	Content
1	.\" RCSid "$Id: mkillum.1,v 1.12 2013/08/11 02:57:49 greg Exp $"
2	.TH RFLUXMTX 1 07/22/14 RADIANCE
3	.SH NAME
4	rfluxmtx - compute flux transfer matrix(es) for RADIANCE scene
5	.SH SYNOPSIS
6	.B rfluxmtx
7	[
8	.B \-v
9	][
10	.B "rcontrib options"
11	]
12	.B "{ sender.rad \| - }"
13	.B receivers.rad
14	.B "[ scene.rad .. ]"
15	.SH DESCRIPTION
16	.I Rfluxmtx
17	samples rays uniformly over the surface given in
18	.I sender.rad
19	and records rays arriving at surfaces in the file
20	.I receivers.rad,
21	producing a flux transfer matrix per receiver.
22	Additional scene surfaces are given in optional
23	.I scene.rad
24	files, which are compiled with the receivers into an octree sent to the
25	.I rcontrib(1)
26	program to do the actual work.
27	If a single hyphen ('-') is given in place of the sender file, then
28	.I rfluxmtx
29	passes ray samples from its standard input directly to
30	.I rcontrib
31	without interpretation.
32	By default, all resulting matrix data are interleaved and sent to the standard output
33	in ASCII format, but this behavior is typically overridden using inline options
34	as described below.
35	.PP
36	The
37	.I \-v
38	option turns on verbose reporting for the number of samples and the executed
39	.I rcontrib
40	command.
41	All other supported options are passed on to
42	.I rcontrib(1).
43	However, the
44	.I \-f,
45	.I \-e,
46	.I \-p,
47	.I \-b,
48	.I \-bn,
49	.I \-m,
50	and
51	.I \-M
52	options are controlled by
53	.I rfluxmtx
54	and may not be set by the user.
55	Also, the
56	.I \-x,
57	.I \-y,
58	and
59	.I \-ld
60	options are ignored unless
61	.I rfluxmtx
62	is invoked in the pass-through mode,
63	in which case they may be needed to generate RADIANCE views from
64	.I vwrays(1).
65	The sample count, unless set by the
66	.I \-c
67	option, defaults to 10000 when a sender file is given, and 1 for pass-through mode.
68	.SH VARIABLES
69	The sender and receiver scene files given to
70	.I rfluxmtx
71	contain controlling parameters in specal comments of the form:
72	.nf
73
74	#@rfluxmtx variable=value ..
75
76	.fi
77	At minimum, both sender and receiver must specify one of the
78	hemisphere sampling types, and there must be at least
79	one surface in each file.
80	.TP 10n
81	.BI h =u
82	Set hemisphere sampling to "uniform," meaning a single bin
83	of (cosine-distributed) samples.
84	In the case of distant "source" primatives, this is the only
85	sampling method that supports arbitrary receiver sizes.
86	The other methods below require a full hemispherical source.
87	.TP
88	.BI h =kf
89	Divide the hemisphere using the LBNL/Klems "full" sampling basis.
90	.TP
91	.BI h =kh
92	Divide the hemisphere using the LBNL/Klems "half" sampling basis.
93	.TP
94	.BI h =kq
95	Divide the hemisphere using the LBNL/Klems "quarter" sampling basis.
96	.TP
97	.BI h =rN
98	Divide the hemisphere using Reinhart's substructuring of the Tregenza
99	sky pattern with
100	.I N
101	divisions in each dimension.
102	If it is not given,
103	.I N
104	defaults to 1, which is just the Tregenza sky.
105	.TP
106	.BI h =scN
107	Subdivide the hemisphere using the Shirley-Chiu square-to-disk mapping with an
108	.I NxN
109	grid over the square.
110	.TP
111	.BI u =[-]{X\|Y\|Z\|ux,uy,uz}
112	Orient the "up" direction for the hemisphere using the indicated axis or direction
113	vector.
114	.TP
115	.BI o =output.mtx
116	Send the matrix data for this receiver to the indicated output file.
117	The file format will be determined by the command-line
118	.I \-fio
119	option and will include an information header unless the
120	.I \-h
121	option was used to turn headers off.
122	(The output file specification is ignored for senders.)\0
123	.PP
124	In normal execution, only a single sender surface is sampled, but it may be
125	comprised of any number of subsurfaces, as in a triangle mesh or similar.
126	The surface normal will be computed as the average of all the constituent
127	subsurfaces.
128	The subsurfaces themselves must be planer, thus only
129	.I polygon
130	and
131	.I ring
132	surface primitives are supported.
133	Other primitives will be silently ignored and will have no effect on the calculation.
134	.PP
135	In the receiver file, the
136	.I source
137	primitive is supported as well, and multiple receivers (and multiple output
138	matrices) are identified by different modifier names.
139	Though it may be counter-intuitive, receivers are often light sources,
140	since samples end up there in a backwards ray-tracing system such as RADIANCE.
141	.PP
142	Rays always eminate from the back side of the sender surface and arrive at the
143	front side of receiver surfaces.
144	In this way, a receiver surface may be reused as a sender in a subsequent
145	.I rfluxmtx
146	calculation and the resulting matrices will concatenate properly.
147	(Note that it is important to keep receiver surfaces together, otherwise a
148	"duplicate modifier" error will result.)\0
149	.SH EXAMPLES
150	To generate a flux transfer matrix connecting input and output apertures
151	on a light pipe:
152	.IP "" .3i
153	rcontrib int_aperture.rad ext_aperture.rad lpipe.rad > lpipe.mtx
154	.SH AUTHOR
155	Greg Ward
156	.SH "SEE ALSO"
157	genBSDF(1), getinfo(1), rcalc(1), rcollate(1), rcontrib(1), rmtxop(1), vwrays(1)