Issues using vtkPReflectionFilter

Hello,

I am trying to use vtkPReflectionFilter to apply symmetry to a surface mesh and I am unable to remove seam at the reflection plane. Here is the code snippet:


  vtkNew<vtkIOSSReader> reader;
  reader->SetFileName(exodusFileName.toLocal8Bit().constData());

  vtkNew<vtkPReflectionFilter> reflection;
  reflection->SetInputConnection(reader->GetOutputPort());
  reflection->SetPlaneToYMin();
  reflection->CopyInputOn();

  vtkNew<vtkMergeBlocks> merge;
  merge->SetInputConnection(reflection->GetOutputPort());
  merge->SetOutputDataSetType(VTK_UNSTRUCTURED_GRID);
  merge->MergePointsOff();

  vtkNew<vtkCleanUnstructuredGrid> clean;
  clean->SetInputConnection(merge->GetOutputPort());
  clean->SetTolerance(0.0);

  vtkNew<vtkGeometryFilter> surface;
  surface->SetInputConnection(clean->GetOutputPort());

  vtkNew<vtkRemoveDuplicatePolys> dedupe;
  dedupe->SetInputConnection(surface->GetOutputPort());

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(dedupe->GetOutputPort());
  mapper->ScalarVisibilityOff();

This code shows the seam when the exodus file contains a surface mesh. If it contains a volume mesh the seam is removed. How can fix this problem?