man/man1/robjutil.1

.\" RCSid "$Id: robjutil.1,v 1.1 2020/03/30 18:28:35 greg Exp $"
.TH ROBJUTIL 1 3/31/20 RADIANCE
.SH NAME
robjutil - operate on Wavefront .OBJ file
.SH SYNOPSIS
.B robjutil
[
.B +/-r
][
.B +/-v
][
.B +/-t
][
.B +/-n
][
.B "+/-m mname"
][
.B "+/-g gname"
][
.B "-c epsilon"
][
.B "-x 'xf spec'"
]
[
.B input.obj ..
]
.SH DESCRIPTION
.I Robjutil
reads and manipulates a Wavefront .OBJ file, removing degenerate and
duplicate faces.
If the
.I +r
option is specified, a Radiance scene description
will be produced on the standard output.
If
.I -r
is given, a modified .OBJ file will be sent to the standard output.
This is the default, and is
typically more useful, since surface normals are better handled by the
.I obj2rad(1)
and
.I obj2mesh(1)
converters.
The latter also preserves local texture coordinates for mapping materials.
The
.I +v
option turns on verbose progress reports.
.PP
The
.I \-t
option tells
.I robjutil
to remove texture coordinates from the input.
The
.I \-n
option will cause all surface normals to be removed.
.PP
The
.I "\-m mname"
option tells
.I robjutil
to remove all faces that use the material
.I mname.
Multiple
.I \-m
options may be given, each with a single (unique) material name.
Alternatively, the
.I "+m mname"
option may be used to specify a material one wishes to keep, discarding the rest.
Multiple
.I +m
options will keep all the named materials.
The
.I \-m
and
.I \+m
options are mutually exclusive.
Similarly, the
.I "\-g gname"
option says to remove all faces belonging to the group
.I gname,
and multiple
.I \-g
options may be given.
There is also a
.I +g
option to save just the named group(s).
.PP
A
.I "\-c epsilon"
parameter may be given to coalesce vertices that are within the given epsilon.
This is useful to improve the connectivity of models that were produced
in a sloppy conversion process from independent polygons.
When producing a Radiance file via the
.I +r
option, there will be no savings in the output size, but there can be
a benefit in reducing the number of "cracks" in the resulting geometry,
at least for triangle mesh input.
.I Robjutil
does not attempt to break up non-planar polygons into triangles,
which is usually not a problem for .OBJ output, but may be for Radiance
scene descriptions (+r).
.PP
The
.I \-x
option may be used to specify a final transform to apply to all
coordinates in the file before output.
This specification must be contained in a single quoted word and
match the standard arguments used by
.I xform(1),
except that the
.I \-a
option is not supported for creating arrays of objects.
Also, any scaling applied does not affect the epsilon value given for
coalescing vertices, as this operation is applied prior to the transform,
even if
.I \-c
appears later in the command line.
.SH EXAMPLES
To remove degenerate and duplicate faces from "orig.obj" and write to "final.rad":
.IP "" .2i
robjutil +r orig.obj > final.rad
.PP
To convert the same file, preserving surface normal interpolation:
.IP "" .2i
robjutil orig.obj | obj2rad > withnormals.rad
.PP
To extract only the groups "cat" and "bell" from the file "kitty.obj" and
write to a Radiance triangle mesh using materials from "kitty.mat":
.IP "" .2i
robjutil +g cat +g bell kitty.obj | obj2mesh -a kitty.mat > kitty.rtm
.PP
To rotate the scene 90 degrees about the Y-axis and scale by 10:
.IP "" .2i
robjutil -x "-ry 90 -s 10" orig.obj > transformed.obj
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
obj2mesh(1), obj2rad(1) oconv(1), xform(1)
Revision:	1.2
Committed:	Thu Apr 2 20:44:15 2020 UTC (5 years, 2 months ago) by greg
Branch:	MAIN
Changes since 1.1:	+24 -2 lines
Log Message:	Added -x option to robjutil to transform .OBJ files
#	Content
1	.\" RCSid "$Id: robjutil.1,v 1.1 2020/03/30 18:28:35 greg Exp $"
2	.TH ROBJUTIL 1 3/31/20 RADIANCE
3	.SH NAME
4	robjutil - operate on Wavefront .OBJ file
5	.SH SYNOPSIS
6	.B robjutil
7	[
8	.B +/-r
9	][
10	.B +/-v
11	][
12	.B +/-t
13	][
14	.B +/-n
15	][
16	.B "+/-m mname"
17	][
18	.B "+/-g gname"
19	][
20	.B "-c epsilon"
21	][
22	.B "-x 'xf spec'"
23	]
24	[
25	.B input.obj ..
26	]
27	.SH DESCRIPTION
28	.I Robjutil
29	reads and manipulates a Wavefront .OBJ file, removing degenerate and
30	duplicate faces.
31	If the
32	.I +r
33	option is specified, a Radiance scene description
34	will be produced on the standard output.
35	If
36	.I -r
37	is given, a modified .OBJ file will be sent to the standard output.
38	This is the default, and is
39	typically more useful, since surface normals are better handled by the
40	.I obj2rad(1)
41	and
42	.I obj2mesh(1)
43	converters.
44	The latter also preserves local texture coordinates for mapping materials.
45	The
46	.I +v
47	option turns on verbose progress reports.
48	.PP
49	The
50	.I \-t
51	option tells
52	.I robjutil
53	to remove texture coordinates from the input.
54	The
55	.I \-n
56	option will cause all surface normals to be removed.
57	.PP
58	The
59	.I "\-m mname"
60	option tells
61	.I robjutil
62	to remove all faces that use the material
63	.I mname.
64	Multiple
65	.I \-m
66	options may be given, each with a single (unique) material name.
67	Alternatively, the
68	.I "+m mname"
69	option may be used to specify a material one wishes to keep, discarding the rest.
70	Multiple
71	.I +m
72	options will keep all the named materials.
73	The
74	.I \-m
75	and
76	.I \+m
77	options are mutually exclusive.
78	Similarly, the
79	.I "\-g gname"
80	option says to remove all faces belonging to the group
81	.I gname,
82	and multiple
83	.I \-g
84	options may be given.
85	There is also a
86	.I +g
87	option to save just the named group(s).
88	.PP
89	A
90	.I "\-c epsilon"
91	parameter may be given to coalesce vertices that are within the given epsilon.
92	This is useful to improve the connectivity of models that were produced
93	in a sloppy conversion process from independent polygons.
94	When producing a Radiance file via the
95	.I +r
96	option, there will be no savings in the output size, but there can be
97	a benefit in reducing the number of "cracks" in the resulting geometry,
98	at least for triangle mesh input.
99	.I Robjutil
100	does not attempt to break up non-planar polygons into triangles,
101	which is usually not a problem for .OBJ output, but may be for Radiance
102	scene descriptions (+r).
103	.PP
104	The
105	.I \-x
106	option may be used to specify a final transform to apply to all
107	coordinates in the file before output.
108	This specification must be contained in a single quoted word and
109	match the standard arguments used by
110	.I xform(1),
111	except that the
112	.I \-a
113	option is not supported for creating arrays of objects.
114	Also, any scaling applied does not affect the epsilon value given for
115	coalescing vertices, as this operation is applied prior to the transform,
116	even if
117	.I \-c
118	appears later in the command line.
119	.SH EXAMPLES
120	To remove degenerate and duplicate faces from "orig.obj" and write to "final.rad":
121	.IP "" .2i
122	robjutil +r orig.obj > final.rad
123	.PP
124	To convert the same file, preserving surface normal interpolation:
125	.IP "" .2i
126	robjutil orig.obj \| obj2rad > withnormals.rad
127	.PP
128	To extract only the groups "cat" and "bell" from the file "kitty.obj" and
129	write to a Radiance triangle mesh using materials from "kitty.mat":
130	.IP "" .2i
131	robjutil +g cat +g bell kitty.obj \| obj2mesh -a kitty.mat > kitty.rtm
132	.PP
133	To rotate the scene 90 degrees about the Y-axis and scale by 10:
134	.IP "" .2i
135	robjutil -x "-ry 90 -s 10" orig.obj > transformed.obj
136	.SH AUTHOR
137	Greg Ward
138	.SH "SEE ALSO"
139	obj2mesh(1), obj2rad(1) oconv(1), xform(1)