"Boundary" of unstructured point data

Tim Hutton T.Hutton at eastman.ucl.ac.uk
Thu Sep 9 11:16:42 EDT 1999

At 09:45 10/09/99 -0500, you wrote:
>Hello All,
>I would like some advice on how to compute the "boundary mesh" of a set
>of points in an UnstructuredGrid dataset. In other words, construct a
>mesh from only the boundary of the set of points.
>The dataset is quite large: ~50,000 points, so Delaunay3D for example is
>prohibitively expensive.
>I thought perhaps some combination of parameters to vtkDelaunay3D might
>do the trick? Apparently vtkExtractEdges and vtkFeatureEdges require
>polygons and dont work on point data alone.  ContourFilter wont do the
>trick either.

If your points are spread throughout the volume, the only way to do this
that I know of is to use Delaunay but I appreciate this would take a long
time for 50,000 points. 

If on the other hand your points are scattered only on the surface of the
object you can use vtkSurfaceReconstructionFilter followed by Marching
Cubes to generate a mesh that approximates the surface.

Hope this is of some help,


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
This email represents the views of the sender alone and must not be
construed as representing the views of the Eastman Dental Institute. It may
contain confidential information and may be protected by law as a legally
privileged document and copyright work. Its content should not be disclosed
and it should not be given or copied to anyone other than the person(s)
named or referenced above. If you have received this email in error, please
contact the sender.

This is the private VTK discussion list.  Please keep messages on-topic.
Check the FAQ at: <http://www.automatrix.com/cgi-bin/vtkfaq>
To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
<majordomo at gsao.med.ge.com>.  For help, send message body containing
"info vtkusers" to the same address.     Live long and prosper.

More information about the vtkusers mailing list