BUG:Really fix the bug on vtkSampleFunction. The problem is that vtkFieldData::GetAbstractArray() adds an array based on names and considers an unamed array only when the string pointer is NULL, not when the string is empty, as the initial names for the scalar array and normal array were the same (empty string), the normal array was replacing the scalar array... Thanks Berk! As vtkImageImport uses the same mechanism, set the initial name to something else than the empty string.