vtkOBJReader - vtkPolyData grouping access ?

When loading a Wavefront OBJ file that has multiple g groups, I noticed that the resulting vtkPolyData when written out as *.vtp retains some of the grouping structure. I discover those groupings when I loaded the exported *.vtp files in ParaView.

While in C++ land dealing with vtkPolyData object, what are the calls for querying such groups ?


If the data are related to points use polydata->GetPointData()->GetArray() otherwise swap GetPointData with GetCellData