mesh

[Tim Hutton]

At 15:11 11/06/99 +0200, Jordi Cabot wrote:
>
>Hello vtkusers,
>
> I've got a set of points which don't lay on the same plane, and I'd
>like to get a kind of mesh with them. I'm trying with Delaunay3D and
>then ExtractEdges but the results are rather ugly, because there are too
>many edges. I'd like that every point gets connected with the nearest 4
>neighbours. How can I do this?

Tricky. I presume the points define the surface of some object, what you
really need is a surface reconstruction algorithm. If your surface is
always convex then Delaunay3D followed by vtkGeometryFilter should give you
what you want. Otherwise try using vtkSurfaceReconstructionFilter followed
by marching cubes but this won't use the original points for the final mesh.

You could try just creating lines to the nearest 4 neighbours of each
point, using vtkPointLocator::FindClosestNPoints but this won't give you a
mesh as such.

It would be very nice to have a kind of Delaunay triangulation for 2D
polygons on a not-quite planar set of points. I have seen this done but
without any code (http://www.parc.xerox.com/csl/members/bern/surface.html).
I would absolutely love to see this algorithm implemented in vtk, the
authors discuss why this approach to surface reconstruction is better than
other methods for visualisation purposes.

Tim.
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Tim Hutton, Research Assistant            Email: T.Hutton at eastman.ucl.ac.uk
MINORI Project                     http://www.eastman.ucl.ac.uk/~dmi/MINORI
Dental and Medical Informatics                   Tel: [+44] (0171) 915 2344
Eastman Dental Institute                         Fax: [+44] (0171) 915 2303
256 Gray's Inn Road, London WC1X 8LD, UK
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