[vtkusers] vtkDelaunay3D: wrong convex hull

[Miguel Sotaquirá]

Hi,

I'm using vtkDelaunay3D to create the local (1-ring neighborhood) convex
hull for each point in a mesh. For now I'm using a synthetic, perfectly
regular, noiseless mesh, where each vertex has exactly 6 neighbors.

I'm having troubles creating this convex hull only on one of the vertices
(the others are computed correctly). In this particular case the convex hull
computed does NOT include one of the six neighbors, as seen on the image
below:

http://tinypic.com/r/2944hag/7

the purple point being the center of the neighborhood, the gray spheres its
neighbors and the gray lines the convex hull obtained from vtkDelaunay3D.

Here's the code I'm using (neighbors are introduced as a polydata named
"pointcloud"):
vtkSmartPointer<vtkDelaunay3D> delaunay3D =
vtkSmartPointer<vtkDelaunay3D>::New();
delaunay3D->SetInput(pointCloud);
delaunay3D->Update();

during execution I get this warning: "vtkDelaunay3D (0x10345a490): 1
degenerate triangles encountered, mesh quality suspect"

How come, since I'm using a synthetic and perfectly regular mesh? As I
mentioned before, for other points (which have the exact same
characteristics) the convex hull is computed correctly.... Also, I've tried
using the methods "SetTolerance" and "BoundingTriangulationOn" of
vtkDelaunay3D but with no success

Thanks!
Miguel
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