GEOMVIEW

Last update: 13.11.01

Le logiciel GEOMVIEW

GEOMVIEW is an interactive program for viewing and manipulating geometric objects, wtitten by staff members of the Geometry Center at 'geom.umn.edu'. See also the GEOMVIEW home page.

      

OOGL File Formats

Conventions:
The objects you can load into GEOMVIEW are called OOGL objects. OOGL stands for "Object Oriented Graphics Library"; it is the library upon GEOMVIEW is built.
Examples of most file types live in GEOMVIEW's 'data/geom' directory.

GEOMVIEW uses normal vectors to determine how an object is shaded. The direction of the normal is significant in this calculation.
When normals are supplied with an object, the direction of the normal is determines by the given data.
When normals are not supplied with the object, GEOMVIEW computes normal vectors automatically; in this case normals point toward the side from which the vertices appear in counterclockwise order.

Object File Formats: ( HTML-tutorial)

• QUAD
• MESH
• Bezier Surfaces
  
  
• OFF
  The convetional suffix for OFF file is 'off'.
  Syntax:
  [C][N][4]OFF # header keyword (optional)
  NVertices NFaces NEdges # NEdges not used or checked
  
  x[0] y[0] z[0] # Verices, possibly with colors
        # and/or normal if COFF or NOFF
  ...
  x[NVertices-1] y[NVertices-1] z[NVertices-1]
  
        # Faces
        # Nv = # vertices on this face
        # v[0] ... v[Nv-1]: vertex indices
        # in range 0..NVertices-1
  Nv v[0] v[1] ... v[Nv-1] colorspec
  ...
        # colorspec continues past v[Nv-1]
        # to end-of-line, may be 0 to 4 numbers
        # nothing: defalut
        # J integer: color map index
        # 3 or 4 integers: RGB[A] values 0..255
  # 3 or 4 floats: RGB[A] values 0..1
  
  OFF files (object file format) represents collections of planar polygons with possibly shared vertices, a convienient way to describe polyhedra. The polygons may be concave but there is no provision for polygons cantaining holes.
  
  An OFF file may begin with the kayword OFF; it's recommened but optional, as many existing files lack this keyword.
  
  Three ASCII intergers follow: NVertices NFaces NEdges. These are the number of vertices, faces, and edges respectively. Current software does not use or check NEdges. It needn't be correct but must be present.
  
  The vertex coordinates follow: dimension * Nvertices floating point values. They're implicitly numbered 0 through Nvertices-1. dimension is either 3 (default) or 4 (specified by the key character 4 directly before OFF in the keyword).
  
  Following these are the face descriptions, typically written with one line per face. Each has the form
  
  N Vert1 Vert2 ... VertN [color]
  
  Here N ist the number of vertices on this face, and Vert1 through VertN are indices into the list of vertices (in range 0..NVertices-1).
  
  The optional color may take several forms. Line breaks are significant here: the color descritption begins after VertN and ends with the end of the line (or the next # comment). A color may be:
  
  nothing: the default color
  
  one integer: index into "the" colormap
  
  three or four integers: RGB and possibly alpha values in the range 0..255
  
  three or four floating-point numbers: RGB and possibly alpha values in the range 0..1
  
  The meaning of "default color" varies. If no face of the object has a color, al inherit the environment's default material color. If some but not all faces have colors, the default is gray (R,G,B,A=0.666).
  
  Example (with color) :
  
  OFF
  25 50 0
  1.300000 0.000000 0.000000
  0.401722 1.236373 0.000000
  -1.051722 0.764121 0.000000
  -1.051722 -0.764121 0.000000
  0.401722 -1.236373 0.000000
  1.092705 0.000000 0.285317
  0.337664 1.039224 0.285317
  -0.884017 0.642276 0.285317
  -0.884017 -0.642276 0.285317
  0.337664 -1.039224 0.285317
  0.757295 0.000000 0.176336
  0.234017 0.720230 0.176336
  -0.612664 0.445127 0.176336
  -0.612664 -0.445127 0.176336
  0.234017 -0.720230 0.176336
  0.757295 0.000000 -0.176336
  0.234017 0.720230 -0.176336
  -0.612664 0.445127 -0.176336
  -0.612664 -0.445127 -0.176336
  0.234017 -0.720230 -0.176336
  1.092705 0.000000 -0.285317
  0.337664 1.039224 -0.285317
  -0.884017 0.642276 -0.285317
  -0.884017 -0.642276 -0.285317
  0.337664 -1.039224 -0.285317
  3 19 20 24 0.653607 0.032241 0.587214
  3 18 24 23 0.653607 0.032241 0.587214
  3 18 19 24 0.653607 0.032241 0.587214
  3 17 23 22 0.653607 0.032241 0.587214
  3 17 18 23 0.653607 0.032241 0.587214
  3 16 22 21 0.653607 0.032241 0.587214
  3 16 17 22 0.653607 0.032241 0.587214
  3 15 20 19 0.653607 0.032241 0.587214
  3 15 21 20 0.653607 0.032241 0.587214
  3 15 16 21 0.653607 0.032241 0.587214
  3 14 15 19 0.653607 0.032241 0.587214
  3 13 19 18 0.653607 0.032241 0.587214
  3 13 14 19 0.653607 0.032241 0.587214
  3 12 18 17 0.653607 0.032241 0.587214
  3 12 13 18 0.653607 0.032241 0.587214
  3 11 17 16 0.653607 0.032241 0.587214
  3 11 12 17 0.653607 0.032241 0.587214
  3 10 15 14 0.653607 0.032241 0.587214
  3 10 16 15 0.653607 0.032241 0.587214
  3 10 11 16 0.653607 0.032241 0.587214
  3 9 10 14 0.653607 0.032241 0.587214
  3 8 14 13 0.653607 0.032241 0.587214
  3 8 9 14 0.653607 0.032241 0.587214
  3 7 13 12 0.653607 0.032241 0.587214
  3 7 8 13 0.653607 0.032241 0.587214
  3 6 12 11 0.653607 0.032241 0.587214
  3 6 7 12 0.653607 0.032241 0.587214
  3 5 10 9 0.653607 0.032241 0.587214
  3 5 11 10 0.653607 0.032241 0.587214
  3 5 6 11 0.653607 0.032241 0.587214
  3 4 23 24 0.653607 0.032241 0.587214
  3 4 5 9 0.653607 0.032241 0.587214
  3 3 22 23 0.653607 0.032241 0.587214
  3 3 9 8 0.653607 0.032241 0.587214
  3 3 4 9 0.653607 0.032241 0.587214
  3 3 23 4 0.653607 0.032241 0.587214
  3 2 21 22 0.653607 0.032241 0.587214
  3 2 8 7 0.653607 0.032241 0.587214
  3 2 3 8 0.653607 0.032241 0.587214
  3 2 22 3 0.653607 0.032241 0.587214
  3 1 20 21 0.653607 0.032241 0.587214
  3 1 7 6 0.653607 0.032241 0.587214
  3 1 2 7 0.653607 0.032241 0.587214
  3 1 21 2 0.653607 0.032241 0.587214
  3 0 24 20 0.653607 0.032241 0.587214
  3 0 4 24 0.653607 0.032241 0.587214
  3 0 5 4 0.653607 0.032241 0.587214
  3 0 6 5 0.653607 0.032241 0.587214
  3 0 1 6 0.653607 0.032241 0.587214
  3 0 20 1 0.653607 0.032241 0.587214
  
  Example (without color) :
  
  OFF
  25 50 0
  1.300000 0.000000 0.000000
  0.401722 1.236373 0.000000
  -1.051722 0.764121 0.000000
  -1.051722 -0.764121 0.000000
  0.401722 -1.236373 0.000000
  1.092705 0.000000 0.285317
  0.337664 1.039224 0.285317
  -0.884017 0.642276 0.285317
  -0.884017 -0.642276 0.285317
  0.337664 -1.039224 0.285317
  0.757295 0.000000 0.176336
  0.234017 0.720230 0.176336
  -0.612664 0.445127 0.176336
  -0.612664 -0.445127 0.176336
  0.234017 -0.720230 0.176336
  0.757295 0.000000 -0.176336
  0.234017 0.720230 -0.176336
  -0.612664 0.445127 -0.176336
  -0.612664 -0.445127 -0.176336
  0.234017 -0.720230 -0.176336
  1.092705 0.000000 -0.285317
  0.337664 1.039224 -0.285317
  -0.884017 0.642276 -0.285317
  -0.884017 -0.642276 -0.285317
  0.337664 -1.039224 -0.285317
  3 19 20 24
  3 18 24 23
  3 18 19 24
  3 17 23 22
  3 17 18 23
  3 16 22 21
  3 16 17 22
  3 15 20 19
  3 15 21 20
  3 15 16 21
  3 14 15 19
  3 13 19 18
  3 13 14 19
  3 12 18 17
  3 12 13 18
  3 11 17 16
  3 11 12 17
  3 10 15 14
  3 10 16 15
  3 10 11 16
  3 9 10 14
  3 8 14 13
  3 8 9 14
  3 7 13 12
  3 7 8 13
  3 6 12 11
  3 6 7 12
  3 5 10 9
  3 5 11 10
  3 5 6 11
  3 4 23 24
  3 4 5 9
  3 3 22 23
  3 3 9 8
  3 3 4 9
  3 3 23 4
  3 2 21 22
  3 2 8 7
  3 2 3 8
  3 2 22 3
  3 1 20 21
  3 1 7 6
  3 1 2 7
  3 1 21 2
  3 0 24 20
  3 0 4 24
  3 0 5 4
  3 0 6 5
  3 0 1 6
  3 0 20 1
  
  
• VECT
• INST
• LIST
• TLIST
• GROUP
• DISCGRP
  

      

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