remove individual points from vtkPoints

Question

I have a question regarding a VTK class called vtkPoints. The class has the functionality to insert individual points, but doesn't have the functionality to remove individual points. This is inconvenient for the case when the view needs to be updated by calling vtkPoints::Modified() to drive the graphics pipeline again to update/re-render the view. The obvious case of re-initializing vtkPoints, adding all points again and updating/re-rendering the view is too slow and resource intensive.

Is there a possible solution to this problem?

Thanks, timecatcher

Answer 1

The example http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/DeletePoint has a rather simple solution. Copy points to another temporary vtkPoints by filtering the id to remove, and shallow-copy it to the original one:

void ReallyDeletePoint(vtkSmartPointer<vtkPoints> points, vtkIdType id)
{
  vtkSmartPointer<vtkPoints> newPoints = 
    vtkSmartPointer<vtkPoints>::New();

  for(vtkIdType i = 0; i < points->GetNumberOfPoints(); i++)
    {
    if(i != id)
      {
      double p[3];
      points->GetPoint(i,p);
      newPoints->InsertNextPoint(p);
      }
    }

  points->ShallowCopy(newPoints);
}