[vtkusers] extract boundary node IDs

[Nico Schlömer]

Hi all,

I've got this vtkUnstructuredGrid here (a triangulation of the Moebius
strip) and I'd like to know the IDs of the boundary nodes. What I do
is

  vtkFeatureEdges * pEdges = vtkFeatureEdges::New();
  pEdges->SetInput( vtkMesh );
  pEdges->BoundaryEdgesOn();
  pEdges->FeatureEdgesOff();
  pEdges->NonManifoldEdgesOff();
  pEdges->ManifoldEdgesOff();
  vtkPolyData * poly = pEdges->GetOutput();

and now I'm not quite sure how to proceed from there. Also, curiously,

  poly->Print( std::cout );

reports "Number of Points: 0".

Any hints?

Cheers,
Nico