Hi, I have an issue with a particular vtkUnstructuredGrid which appears to get corrupted when using DeepCopy: vtkSmartPointer<vtkXMLUnstructuredGridReader> reader = vtkSmartPointer<vtkXMLUnstructuredGridReader>::New(); reader->SetFileName("VoronoiCells.vtu"); reader->Update(); vtkSmartPointer<vtkUnstructuredGrid> ug = vtkSmartPointer<vtkUnstructuredGrid>::New(); ug->DeepCopy(reader->GetOutput()); vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer = vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New(); writer->SetInputData(ug); writer->SetFileName("VoronoiCells-after-deepcopy.vtu"); writer->Update(); I will attach the specific grid VoronoiCells.vtu for which the corruption happens. I'll also attach screenshots from paraview for the original file and the output from the corrupted file. [VoronoiCells-after-deepcopy.vtu](/uploads/2c3afe8572a01e53b33a63ccb8e1405c/VoronoiCells-after-deepcopy.vtu) [VoronoiCells.vtu](/uploads/c988908796fd3ce9f572e8690c3de0de/VoronoiCells.vtu)