mesh

[Jordi Cabot]

Hi, 

I'm rather confused and I don't know how to get the results I want.
Sorry if my questions are too simple.

 What I've got:

 - polydata representing the brain surface (Marching Cubes ->Decimate
->Smoothing	 	      ->Stripping)

 - a set of points resulting from the intersection of rays with the
brain.

 - scalars associated to these points.

 What I want:

 - Actually the set of points defines a matrix 10x10. I'd like to color
the part of the brain covered by this matrix and leave the rest of the
brain uncolored. In other words, I'd like to project the matrix to the
brain, knowing the correspondance between the 10x10 points in the matrix
and in the brain, and interpolating the rest of the points.

 What I do:

 - Right now I just put a glyph (sphere) in the intersection points and
I color the spheres. Maybe with the probe filter ...

 Thanks,

jordi


> 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.
> ---------------------------------------------------------------------------
> 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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