Hello,
Am I misunderstanding how VTK uses vtkInformation in pipelines?
Yes, the information object used by a vtkDataObject has different keys than the one used in a vtkAlgorithm.
Some information keys like FIELD_* are used in vtkAlgorithm instances to propagate metadata up/down the pipeline. Those keys are not used in the information objects of vtkDataObject.
Some examples of keys used in vtkPolyData’s information object are vtkDataObject.DATA_EXTENT_TYPE, vtkDataObject.DATA_PIECE_NUMBER, vtkDataObject.DATA_NUMBER_OF_PIECES and vtkDataObject.DATA_NUMBER_OF_GHOST_LEVELS.
I’m not sure if there is a document listing the usage of information keys.
Hope this helps.