Is there a plan to move from a vtkIdTypeArray to this vtkCellArray structure or something equivalent for faces in vtkUnstructuredGrid ?
Then the method
void vtkUnstructuredGrid::SetCells( vtkUnsignedCharArray * cellTypes, vtkIdTypeArray * cellLocations, vtkCellArray * cells, vtkIdTypeArray * faceLocations, vtkIdTypeArray * faces)
could be replaced by something like that:
void vtkUnstructuredGrid::SetCells( vtkUnsignedCharArray * cellTypes, vtkCellArray * cells, vtkFaceArray* faces)
It looks cleaner.