Off the top of my head; You might try to sweep two grids from opposite sides of the vertex set to create two meshes. Kind of like stretching a rubber sheet over a board that has nails sticking out. Then weld the two grids together. Enforcing the validity of such a shell would be a pain though.
-tero
-----Original Message-----
From: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]]On Behalf Of RWGRAY
Sent: 11. maaliskuuta 2003 20:39
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] AW: [JAVA3D] How to form the Geometry?
I was just using the Icosahedron as an example. Could be that the
polyhedron has 120 vertices or more. I don't want to work out by hand which
vertex is connect to which other vertices. I'd like a program to figure
that all out. Could be a mixed (concave/convex) polyhedron. The terrain
correspondence is pretty good, but I know the "terrain" bends around and
closes on itself to form a polyhedron of some kind.
Anyone have an example of such a method?
Cheers,
Bob Gray
-----Original Message-----
From: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]]On Behalf Of White Morph
Sent: Tuesday, March 11, 2003 1:22 PM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] AW: [JAVA3D] How to form the Geometry?
If you just know the coordinates of a bunch of vertices, no other
topological information, then the problem is like the terrain modeling,
in which only a grid of elevation data known. For this kind of problem,
I think there are lot of algorithms and programs for it. Delaunay
triangulation is a popular algorithm for that.
For your example, if you know it's a Icosahedron, then you have the
topological information, I don't know why you say you don't have other
information.
---white
>I don't know of any 3D program which takes an array of arbitrary
coordinates
>and transform them into a 3d shape without giving more informations on how
>to create the faces.
>
>However, if you know that you have some sort of aprox. regular shape, you
>can do some maths to determine how the faces should look like. First,
>determine the geometrical center of your polyhedron. Then you can for each
>point determine the angles phi & theta relative to the center of the shape.
>That will help you to arrage the points in a (phi, theta) grid on which you
>can perform a triangulation.
>
>If you know some more info about the points, like the order of them, you
>should try to use that.
>
>Cheers,
>
>Florin
>
>-----Urspr�ngliche Nachricht-----
>Von: RWGRAY [mailto:[EMAIL PROTECTED]]
>Gesendet: Dienstag, 11. M�rz 2003 16:57
>An: [EMAIL PROTECTED]
>Betreff: [JAVA3D] How to form the Geometry?
>
>
>Is there a class/method/utility which will take an array of polyhedron
>vertex coordinates and return a TriangularArray for the polyhedron?
>
>For example, I have the coordinates for an Icosahedron, but no other
>information. Is there a utility I can call with these coordinates to get
>back a TriangleArray for the Icosahedron?
>
>I looked at GeometryInfo, but it looks like you need to first know which
>combination of vertex coordinates forms the faces of the polyhedron.
>
>Cheers,
>Bob Gray
>
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