man/man1/gensurf.1

.\" RCSid "$Id"
.TH GENSURF 1 11/15/93 RADIANCE
.SH NAME
gensurf - generate a RADIANCE description of a curved surface
.SH SYNOPSIS
.B "gensurf mat name 'x(s,t)' 'y(s,t)' 'z(s,t)' m n"
[
.B "\-e expr"
][
.B "\-f file"
][
.B \-s
]
.br
.B "gensurf mat name 'x(s,t)' 'y(s,t)' dfile m n"
[
.B "\-e expr"
][
.B "\-f file"
][
.B \-s
]
.br
.B "gensurf mat name dfile dfile dfile m n"
[
.B \-s
]
.SH DESCRIPTION
.I Gensurf
produces a RADIANCE scene description of a
functional surface defined by the parametric equations
.I x(s,t),
.I y(s,t),
and
.I z(s,t).
The surface normal is defined by the right hand rule as
applied to
.I (s,t).
.I S
will vary from 0 to 1 in steps of
.I 1/m,
and
.I t
will vary from 0 to 1 in steps of
.I 1/n.
The surface will be composed of
.I 2*m*n
or fewer triangles and quadrilaterals.
The expressions are of the same type used in RADIANCE
function files.
Auxiliary expressions and/or files may be specified
in any number of
.I \-e
and
.I \-f
options.
The
.I \-s
option adds smoothing (surface normal interpolation) to the surface.
.PP
Rough holes may be cut in the mesh by defining a valid(s,t) function.
Where this function is positive, polygon vertices will be produced.
Where it is negative, no geometry will be output.
Surface normal interpolation will ignore any invalid vertices.
.PP
The second invocation form reads z data values from the file
.I dfile.
This file must give either m*n or (m+1)*(n+1) floating point z
values.
If m*n values are given, then the values correspond to the centroid
of each quadrilateral region.
If (m+1)*(n+1) values are given, then the values correspond to the
vertices of each quadrilateral region.
The ordering of the data in the file is such that the s values are
changing faster than the t values.
If a minus ('-') is given for
.I dfile,
then the values are read from the standard input.
.PP
The third invocation form is used to read coordinate triplets from a
file or the standard input.
The three
.I dfile
arguments must all be the same, and the corresponding file must
contain three floating point values for each point location.
The ordering and other details are the same as those described
for z value files above.
.SH EXAMPLE
To generate a tesselated sphere:
.IP "" .2i
gensurf crystal ball 'sin(PI*s)*cos(2*PI*t)' 'cos(PI*s)' 'sin(PI*s)*sin(2*PI*t)' 7 10
.PP
To generate a 10x20 smoothed height field from 12 recorded vertex
z values:
.IP "" .2i
gensurf dirt ground '10*s' '20*t' height.dat 2 3 -s
.SH AUTHOR
Greg Ward
.SH BUGS
The smoothing operation requires that functions be defined
beyond the [0,1] boundaries of s and t.
.SH "SEE ALSO"
calc(1), genbox(1), genrev(1), genworm(1), rpict(1), rview(1), xform(1)
Revision:	1.1
Committed:	Tue Mar 11 19:20:21 2003 UTC (21 years, 6 months ago) by greg
Branch:	MAIN
Log Message:	Added documentation to repository
#	Content
1	.\" RCSid "$Id"
2	.TH GENSURF 1 11/15/93 RADIANCE
3	.SH NAME
4	gensurf - generate a RADIANCE description of a curved surface
5	.SH SYNOPSIS
6	.B "gensurf mat name 'x(s,t)' 'y(s,t)' 'z(s,t)' m n"
7	[
8	.B "\-e expr"
9	][
10	.B "\-f file"
11	][
12	.B \-s
13	]
14	.br
15	.B "gensurf mat name 'x(s,t)' 'y(s,t)' dfile m n"
16	[
17	.B "\-e expr"
18	][
19	.B "\-f file"
20	][
21	.B \-s
22	]
23	.br
24	.B "gensurf mat name dfile dfile dfile m n"
25	[
26	.B \-s
27	]
28	.SH DESCRIPTION
29	.I Gensurf
30	produces a RADIANCE scene description of a
31	functional surface defined by the parametric equations
32	.I x(s,t),
33	.I y(s,t),
34	and
35	.I z(s,t).
36	The surface normal is defined by the right hand rule as
37	applied to
38	.I (s,t).
39	.I S
40	will vary from 0 to 1 in steps of
41	.I 1/m,
42	and
43	.I t
44	will vary from 0 to 1 in steps of
45	.I 1/n.
46	The surface will be composed of
47	.I 2mn
48	or fewer triangles and quadrilaterals.
49	The expressions are of the same type used in RADIANCE
50	function files.
51	Auxiliary expressions and/or files may be specified
52	in any number of
53	.I \-e
54	and
55	.I \-f
56	options.
57	The
58	.I \-s
59	option adds smoothing (surface normal interpolation) to the surface.
60	.PP
61	Rough holes may be cut in the mesh by defining a valid(s,t) function.
62	Where this function is positive, polygon vertices will be produced.
63	Where it is negative, no geometry will be output.
64	Surface normal interpolation will ignore any invalid vertices.
65	.PP
66	The second invocation form reads z data values from the file
67	.I dfile.
68	This file must give either mn or (m+1)(n+1) floating point z
69	values.
70	If m*n values are given, then the values correspond to the centroid
71	of each quadrilateral region.
72	If (m+1)*(n+1) values are given, then the values correspond to the
73	vertices of each quadrilateral region.
74	The ordering of the data in the file is such that the s values are
75	changing faster than the t values.
76	If a minus ('-') is given for
77	.I dfile,
78	then the values are read from the standard input.
79	.PP
80	The third invocation form is used to read coordinate triplets from a
81	file or the standard input.
82	The three
83	.I dfile
84	arguments must all be the same, and the corresponding file must
85	contain three floating point values for each point location.
86	The ordering and other details are the same as those described
87	for z value files above.
88	.SH EXAMPLE
89	To generate a tesselated sphere:
90	.IP "" .2i
91	gensurf crystal ball 'sin(PIs)cos(2PIt)' 'cos(PIs)' 'sin(PIs)sin(2PI*t)' 7 10
92	.PP
93	To generate a 10x20 smoothed height field from 12 recorded vertex
94	z values:
95	.IP "" .2i
96	gensurf dirt ground '10s' '20t' height.dat 2 3 -s
97	.SH AUTHOR
98	Greg Ward
99	.SH BUGS
100	The smoothing operation requires that functions be defined
101	beyond the [0,1] boundaries of s and t.
102	.SH "SEE ALSO"
103	calc(1), genbox(1), genrev(1), genworm(1), rpict(1), rview(1), xform(1)