[vtkusers] Please help: 3D Delaunay

[Bryn Lloyd]

Hi Julio,

Try the function

vtkUnstructuredGrid::GetPoint(int i, double p[3])

it will copy the coordinates of a given point i into the double array p.

delaunay->GetOutput() is a vtkUnstructuredGrid (is a vtkPointSet).


-Bryn



Julio Pastrana wrote:
> Hello vtk experts,
> 
> I really really need some help 
> with the vtkDelaunay3D.
> 
> I am using the example that computes the Convexhull with vtkDelaunay3D.
> Nevertheless, I am having a really hard time to get the calculated
> vertices coordinates. I just need the X,Y,Z coordinates after the
> delaunay triangulation, the points that satisfied the delaunay
> condition.
> 
> I was trying with <vtkXMLUnstructuredGridWriter> but the output file 
> is something I cannot understand.
> 
> Is there some one out there that could help me out???
> I just need to extract the x,y,z coordinates out of the UnstructuredGrid
> I have also tried with GetPointCells and GetCellPoints but so far no
> luck.
> 
> I am attaching the code
> 
> Thank you very much for your help 
> 
> Sincerely,
> Julio
> 
> CODE: 
> -----------------------------------------------------------------------------------------------------------
>   //Create some random points
>  
>   vtkSmartPointer<vtkPoints> Points = vtkSmartPointer< vtkPoints
>> ::New();
>   vtkSmartPointer<vtkCellArray> Vertices =
> vtkSmartPointer<vtkCellArray>::New();
>  
>  //point cloud;
>   for(unsigned int i = 0; i < 50; i++)
>     {
>     vtkIdType pid[1];
>     float x = drand48()*30;
>     float y = drand48()*30;
>     float z = drand48()*30;
>     //cerr << x << "\t" << y << "\t" << z <<"\n";
>     
>     pid[0] = Points->InsertNextPoint(x,y,z);
>     Vertices->InsertNextCell ( 1,pid );
>     }
>  
>   vtkSmartPointer< vtkPolyData> Polydata =
> vtkSmartPointer<vtkPolyData>::New();
>   Polydata->SetPoints(Points);
>   Polydata->SetVerts(Vertices);
>   
>   // Create the convex hull of the point cloud
>   vtkSmartPointer< vtkDelaunay3D > delaunay = vtkSmartPointer<
> vtkDelaunay3D >::New();
>   delaunay->SetAlpha(2);
>   delaunay->SetTolerance(0.5);
>   delaunay->BoundingTriangulationOff ();
> 
>   cerr << "Alpha value :"<< delaunay->GetAlpha () << "\tTolerance "<<
> delaunay->GetTolerance() << "\n";
>   delaunay->SetInput(Polydata);
>   delaunay->Update();
> 
> 
>  
>   vtkSmartPointer<vtkXMLUnstructuredGridWriter> OutputWriter =
> vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
>   OutputWriter->SetFileName("output.vtu");
>   OutputWriter->SetInput(delaunay->GetOutput());
>   OutputWriter->Write();
>  
> 
> 
>   vtkSmartPointer<vtkUnstructuredGrid> dataSet
> =vtkSmartPointer<vtkUnstructuredGrid>::New();
>   dataSet = delaunay->GetOutput();
>   cerr << "Numver of cells : "  << dataSet->GetNumberOfCells () << "\n";
>   
> 
> 
>   //HOW DO I GET THE X,Y,Z coordinates
>   //Out of the delaunay->GetOutput()
> -----------------------------------------------------------------------------------------------------------
> 
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