man/man1/oconv.1

.\" RCSid "$Id: oconv.1,v 1.7 2004/04/21 15:01:46 greg Exp $"
.TH OCONV 1 8/15/95 RADIANCE
.SH NAME
oconv - create an octree from a RADIANCE scene description
.SH SYNOPSIS
.B oconv
[
.B "\-i octree"
|
.B "\-b xmin ymin zmin size
][
.B "\-n objlim"
][
.B "\-r maxres"
][
.B \-f
][
.B \-w
][
-
]
[
.B "input .."
]
.SH DESCRIPTION
.I Oconv
adds each scene description
.I input
to
.I octree
and sends the result to the standard output.
Each
.I input
can be either a file name, or a command (enclosed in quotes
and preceded by a `!').
Similarly, the octree input may be given as a command preceded
by a `!'.
If any of the surfaces will not fit in
.I octree,
an error message is printed and the program aborts.
If no
.I octree
is given, a new one is created large enough for
all of the surfaces.
.PP
The
.I \-b
option allows the user to give a bounding cube for the
scene, starting at
.I "xmin ymin zmin"
and having a side length
.I size.
If the cube does not contain all of the surfaces, an error results.
The
.I \-b
and
.I \-i
options are mutually exclusive.
.PP
The
.I \-n
option specifies the maximum surface set size for
each voxel.
Larger numbers result in quicker octree generation,
but potentially slower rendering.
Smaller values may or may not produce faster renderings,
since the default number (6) is close to optimal for most scenes.
.PP
The
.I \-r
option specifies the maximum octree resolution.
This should be greater than or equal to the ratio of the largest
and smallest dimensions in the scene (ie. surface size or distance between 
surfaces).
The default is 16384.
.PP
The
.I \-f
option produces a frozen octree containing all the scene information.
Normally, only a reference to the scene files is stored in the
octree, and changes to those files may invalidate the result.
The freeze option is useful when the octree file's
integrity and loading speed is more important than its size, or
when the octree is to be relocated to another directory, and is
especially useful for creating library objects for the "instance"
primitive type.
If the input octree is frozen, the output will be also.
.PP
The
.I \-w
option suppresses warnings.
.PP
A hyphen by itself ('-') tells
.I oconv
to read scene data from its standard input.
This also implies the
.I \-f
option.
.PP
The only scene file changes that do not require octree regeneration are
modifications to non-surface parameters.
If the coordinates of a surface are changed, or any primitives are added
or deleted, oconv must be run again.
Programs will abort with a "stale octree" message
if they detect any dangerous inconsistencies between
the octree and the input files.
.PP
Although the octree file format is binary, it is meant to be portable
between machines.
The only limitation is that machines with radically different integer
sizes will not work together.
For the best results, the \-f option should be used if an octree is
to be used in different environments.
.SH DIAGNOSTICS
There are four basic error types reported by oconv:
.IP
warning - a non-fatal input-related error
.IP
fatal - an unrecoverable input-related error
.IP
system - a system-related error
.IP
internal - a fatal error related to program limitations
.IP
consistency - a program-caused error
.PP
Most errors are self-explanatory.
However, the following internal errors should be mentioned:
.IP "Too many scene files"
Reduce the number of scene files by combining them or using calls
to xform(1) within files to create a hierarchy.
.IP "Set overflow in addobject (id)"
This error occurs when too many surfaces are close together in a
scene.
Either too many surfaces are lying right on top of each other,
or the bounding cube is inflated from an oversized object
or an improper
.I \-b
specification.
If hundreds of triangles come together at a common vertex, it may
not be possible to create an octree from the object.
This happens most often when inane CAD systems create spheres using
a polar tessellation.
Chances are, the surface "id" is near one of those causing the problem.
.IP "Hash table overflow in fullnode"
This error is caused by too many surfaces.
If it is possible to create an octree for the scene at all,
it will have to be done in stages using the
.I \-i
option.
.SH EXAMPLE
To add book1, book2 and a
transformed book3 to the octree ``scene.oct'':
.IP "" .2i
oconv \-i scene.oct book1 book2 '\\!xform \-rz 30 book3' > newscene.oct
.SH AUTHOR
Greg Ward
.SH NOTES
In the octree, the names of the scene files are stored rather
than the scene information.
This means that a new octree must be generated whenever the
scene files are changed or moved.
Also, an octree that has been moved to a new directory will not be able to find
scene files with relative pathnames.
The freeze option avoids these problems.
.I make(1)
or
.I rad(1)
can be used to automate octree creation and maintenance.
.SH "SEE ALSO"
getbbox(1), getinfo(1), make(1), obj2mesh(1), rad(1),
rpict(1), rvu(1), rtrace(1), xform(1)
Revision:	1.8
Committed:	Tue Sep 4 17:36:40 2007 UTC (18 years, 2 months ago) by greg
Branch:	MAIN
CVS Tags:	rad5R4, rad5R2, rad5R3, rad5R0, rad5R1, rad4R2, rad6R0, rad4R1, rad4R0, rad3R9, rad4R2P1, rad4R2P2, HEAD
Changes since 1.7:	+3 -3 lines
Log Message:	Added backslashes in front of hyphens (thanks to Bernd Zeimetz for his effort)
#	User	Rev	Content
1	greg	1.8	.\" RCSid "$Id: oconv.1,v 1.7 2004/04/21 15:01:46 greg Exp $"
2	greg	1.1	.TH OCONV 1 8/15/95 RADIANCE
3			.SH NAME
4			oconv - create an octree from a RADIANCE scene description
5			.SH SYNOPSIS
6			.B oconv
7			[
8			.B "\-i octree"
9			\|
10			.B "\-b xmin ymin zmin size
11			][
12			.B "\-n objlim"
13			][
14			.B "\-r maxres"
15			][
16			.B \-f
17			][
18			.B \-w
19			][
20			-
21			]
22			[
23			.B "input .."
24			]
25			.SH DESCRIPTION
26			.I Oconv
27			adds each scene description
28			.I input
29			to
30			.I octree
31			and sends the result to the standard output.
32			Each
33			.I input
34			can be either a file name, or a command (enclosed in quotes
35			and preceded by a `!').
36			Similarly, the octree input may be given as a command preceded
37			by a `!'.
38			If any of the surfaces will not fit in
39			.I octree,
40			an error message is printed and the program aborts.
41			If no
42			.I octree
43			is given, a new one is created large enough for
44			all of the surfaces.
45			.PP
46			The
47			.I \-b
48			option allows the user to give a bounding cube for the
49			scene, starting at
50			.I "xmin ymin zmin"
51			and having a side length
52			.I size.
53			If the cube does not contain all of the surfaces, an error results.
54			The
55			.I \-b
56			and
57			.I \-i
58			options are mutually exclusive.
59			.PP
60			The
61			.I \-n
62			option specifies the maximum surface set size for
63			each voxel.
64			Larger numbers result in quicker octree generation,
65			but potentially slower rendering.
66			Smaller values may or may not produce faster renderings,
67	greg	1.3	since the default number (6) is close to optimal for most scenes.
68	greg	1.1	.PP
69			The
70			.I \-r
71			option specifies the maximum octree resolution.
72			This should be greater than or equal to the ratio of the largest
73			and smallest dimensions in the scene (ie. surface size or distance between
74			surfaces).
75	greg	1.3	The default is 16384.
76	greg	1.1	.PP
77			The
78			.I \-f
79			option produces a frozen octree containing all the scene information.
80			Normally, only a reference to the scene files is stored in the
81			octree, and changes to those files may invalidate the result.
82			The freeze option is useful when the octree file's
83			integrity and loading speed is more important than its size, or
84			when the octree is to be relocated to another directory, and is
85			especially useful for creating library objects for the "instance"
86			primitive type.
87			If the input octree is frozen, the output will be also.
88			.PP
89			The
90			.I \-w
91			option suppresses warnings.
92			.PP
93			A hyphen by itself ('-') tells
94			.I oconv
95			to read scene data from its standard input.
96			This also implies the
97			.I \-f
98			option.
99			.PP
100			The only scene file changes that do not require octree regeneration are
101			modifications to non-surface parameters.
102			If the coordinates of a surface are changed, or any primitives are added
103			or deleted, oconv must be run again.
104			Programs will abort with a "stale octree" message
105			if they detect any dangerous inconsistencies between
106			the octree and the input files.
107			.PP
108			Although the octree file format is binary, it is meant to be portable
109			between machines.
110			The only limitation is that machines with radically different integer
111			sizes will not work together.
112	greg	1.8	For the best results, the \-f option should be used if an octree is
113	greg	1.1	to be used in different environments.
114			.SH DIAGNOSTICS
115			There are four basic error types reported by oconv:
116			.IP
117			warning - a non-fatal input-related error
118			.IP
119			fatal - an unrecoverable input-related error
120			.IP
121			system - a system-related error
122			.IP
123			internal - a fatal error related to program limitations
124			.IP
125			consistency - a program-caused error
126			.PP
127			Most errors are self-explanatory.
128			However, the following internal errors should be mentioned:
129			.IP "Too many scene files"
130			Reduce the number of scene files by combining them or using calls
131			to xform(1) within files to create a hierarchy.
132			.IP "Set overflow in addobject (id)"
133			This error occurs when too many surfaces are close together in a
134			scene.
135			Either too many surfaces are lying right on top of each other,
136			or the bounding cube is inflated from an oversized object
137			or an improper
138			.I \-b
139			specification.
140	greg	1.6	If hundreds of triangles come together at a common vertex, it may
141			not be possible to create an octree from the object.
142			This happens most often when inane CAD systems create spheres using
143	greg	1.7	a polar tessellation.
144	greg	1.1	Chances are, the surface "id" is near one of those causing the problem.
145			.IP "Hash table overflow in fullnode"
146			This error is caused by too many surfaces.
147			If it is possible to create an octree for the scene at all,
148			it will have to be done in stages using the
149			.I \-i
150			option.
151			.SH EXAMPLE
152			To add book1, book2 and a
153			transformed book3 to the octree ``scene.oct'':
154			.IP "" .2i
155	greg	1.8	oconv \-i scene.oct book1 book2 '\\!xform \-rz 30 book3' > newscene.oct
156	greg	1.1	.SH AUTHOR
157			Greg Ward
158			.SH NOTES
159			In the octree, the names of the scene files are stored rather
160			than the scene information.
161			This means that a new octree must be generated whenever the
162			scene files are changed or moved.
163			Also, an octree that has been moved to a new directory will not be able to find
164			scene files with relative pathnames.
165			The freeze option avoids these problems.
166			.I make(1)
167			or
168			.I rad(1)
169			can be used to automate octree creation and maintenance.
170			.SH "SEE ALSO"
171	greg	1.2	getbbox(1), getinfo(1), make(1), obj2mesh(1), rad(1),
172	greg	1.5	rpict(1), rvu(1), rtrace(1), xform(1)