[vtkusers] How to get a list of ids of points in boundary from unstructured grid ??

[Fabio Canesin]

Hi all, can someone provide a python or c++ example of getting a list
with the Ids of points in the boundary of a unstructured grid ?? Since
my grid is regular (for now) I'm doing some ugly loop like:

  idlist = []
  ncells = UnstructuredGrid.GetNumberOfCells()
  for idx in xrange(ncells):
        p = UnstructuredGrid.GetPoint(idx)
        #Check if x less them 1
        if p[0] < 1:
            idlist.append(idx)

I have saw the example that uses vtkFeatureEdge but it asks for a
vtkData and crashs if I use the vtkUnstructuredGrid in SetInput.

Best regards,
Fábio