-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathmaniviewhelp
157 lines (128 loc) · 6.16 KB
/
maniviewhelp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
Maniview explores three-dimensional manifolds and orbifolds
from "within". You navigate as if you lived inside the
space. This means, in practice, that you will be within
a tessellation of hyperbolic, euclidean, or spherical
space by a discrete groups of motions. Maniview works
in cooperation with Geomview.
The application is structured around a main menu
which accesses several panels. To begin with,
use the 'Load' panel to load a discrete group,
which is the basic data structure used by Maniview.
LOAD
The format for discrete groups is described in
the man page discgrp(5). The default is the three
dimensional torus. Other files that are provided with
the release include borrom4.dgp (a hyperbolic orbifold)
and 120.dgp (the Poincare homology sphere, a spherical
manifold).
Maniview looks for the entered file first in the
current directory and then in the $GEOMDATA/groups
directory. The 'geomview' script usually sets $GEOMDATA,
but you can set it by hand if you wish using 'setenv'.
By activating the buttons on the Load panel you can
choose instead to load geometry to be tessellated by the group
(depress the 'Load Geom' button); to load a geometry
file to represent the camera, depress the 'Load Camgeom'
button.
SAVE
Use the 'Save' menu option to save the current discrete
group to a file. Activate the 'Save Geom' button to
explicitly save the currently displayed geometry with
the group; use the 'Save Group' button to save the
currently displayed list of group elements with the
group.
DISPLAY
You can control display characteristics through the
Display panel. The toggles control how the
discrete group draws itself. To activate a property,
depress its button by clicking on it. Deactivation
works in the inverse manner.
centercam: toggle controls whether to keep the observer
centered in the central fundamental domain.
draw dirdom: will cause the Dirichlet domain geometry to
be displayed (see BASIC TILE panel below for more).
drawgeom: will cause any other geometry you have supplied
to be displayed. (see BASIC TILE panel below for more).
showcam: will tessellate an image of the camera or observer.
The geometry for the camera can be loaded using the LOAD
panel (see above).
cull: will attempt to ignore group elements which are not
visible. It is provided as an option as long as it
hasn't been fully debugged.
software shading: allows you to toggle between hardware and
software shading. Hardware shading is correct only
for Euclidean groups.
Finally, three sliders control the lighting model.
The first 'atten1' influences the attenuation of light
intensity as a function of the distance d of the light source
to the object. For the hyperbolic and spherical case this value
appears in an expression of the form exp(-atten1 d).
This is reasonable for hyperbolic geometry and used in
spherical geometry to provide depth cueing. In the
Euclidean case, atten1 appears in an expression of the
form 1/(d^atten1).
The other two sliders, 'fogfree' and 'fog', control the presence
of fog in the lighting model. 'fogfree' specifies a radius around
the observer which is free of fog. 'fog' is a constant which
appears in an expression of the form exp( -fog d') where
d' = d - fogfree, where d is the distance from the eye to the
surface and d' is clamped to zero if it's negative.
ENUMERATE
The 'Enumerate' panel controls how many and which group
elements are displayed. 'worddepth' is an integer value
which specifies the maximum length of a string, in the
generators of the group, which is to be used. (Use the double
arrows to control this counter, since it must have an
integer value.) 'tesselation radius' controls how far away
the group element may move the center point (this is controlled
from the BASIC TILE panel). These two contraints work as a
Boolean 'and': both must be satisfied for a group element to
be displayed.
BASIC TILE
This panel controls the geometry that is tessellated by
the discrete group. There are basically two modes:
Dirichlet domain, and user-supplied geometry. When the
former button is depressed, the widgets control the computation
of a Dirichlet domain. There are positioning widgets to specify
an (x,y,z) point, and a 'Reset' button to return it to the
default (0,0,0). In the current version, a full copy of
the Dirichlet domain is displayed in wireframe and a smaller copy
with cusps truncated (in the hyperbolic case) is displayed with
face-shading. The amount of scaling of this second copy is
controlled by the slider labeled 'scale factor'. A maximum value of
1.0 results in images which completely fill space and hence
cannot be seen through or around. NOTE: The Dirichlet domain
will be displayed if and only if the 'drawdirdom' button
on the DISPLAY panel is depressed.
Operation in 'user geometry' mode is as follows:
If other geometry has been provided for display via the LOAD
panel or in the original data file, the widgets in this panel
are interpreted to give a translation and a scale for
the supplied geometry, in the obvious way.
NOTE: This geometry will be displayed if and only if
the 'drawgeom' button in the DISPLAY panel is depressed,
INFO
Brings up a panel saying who wrote this module and how
you can acquire it.
HELP
shows this panel.
SEE ALSO
There are connections from snappea and eucsyms to maniview.
See eucsyms(1).
BUGS and NOTES
Sometimes you might need to toggle the 'software shading'
button on the Display menu, to get geomview synchronized
with maniview. This may be needed particularly after loading
a discrete group that changes the metric.
Maniview forces the camera to be the target. This allows
the user to use 'fly' mode in the desired way when 'centercam'
mode is active. In other cases this setting might not be
expected and you'll need to select the appropriate target
in geomview to override this.
The use of an (x,y,z) locator for Dirichlet domain is
appropriate for euclidean and hyperbolic space but really
ought to be fully 4D for the spherical case.
Because geomview currently doesn't allow the use of finite
light sources, maniview turns off Geomview lights and creates
its own fixed lights. Finite light sources are important
since they give good depth cueing.