[vtkusers] Delaunay surface triangulation in 3D

[Matthias Riechmann]

Hi Doug,

as far as I remember using vtk's delaunay, you have to think two 
dimensional even if its a three dimensional set of points that you want 
to form a surface: You can specify a transform to the vtkDelaunay2D 
filter, so if you have a bunch of points forming more or less a sphere, 
you just have to give the filter a vtkSphericalTransform. Then it can 
assemble the surface from the phi and theta coordinates ignoring r. Of 
course you have to transform the points in a way so their center is in 
the neighbourhood of (0, 0, 0).

For more details see the documentation of vtkDelaunay2D.


Matthias




Doug Hackworth schrieb:
> 
> Greetings.  I have a set of N points that reside on the surface of a 
> sphere, and I'd like to create a triangular (not tetrahedral) mesh 
> between these points via Delaunay triangulation.  Using vtkDelaunay2D is 
> out because it does a different thing (ignoring the Z-coordinate during 
> its triangulation).  And using vtkDelaunay3D only does part of the right 
> thing -- it appears to triangulate the surface points nicely, but also 
> creates (as its primary function) a tetrahedral mesh among all the 
> points in 3 dimensions.
> 
> How can I get a triangulated surface?  Just to be clear on what I want, 
> the end result should be a hollow volume of triangles, rather like a 
> geodesic dome.  That make sense?
> 
> It seems as if using vtkDelaunay3D and then extracting the surface 
> triangles only could be a promising course of action, but I have no idea 
> how to do this (I'm also not sure that it's guaranteed to produce the 
> right result).  Can someone offer some guidance on this?  Is there an 
> alternative method that would be better?  Please, offer me your wisdom.  
> :-)
> 
> Thanks,
> Doug
> 
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