    reader = vtkPLYReader()
    reader.SetFileName(filename)
    reader.Update()

    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(reader.GetOutputPort())
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLpoly_dataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLPolyDataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == ".vtp":
        reader = vtkXMLPolyDataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLPolyDataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLPolyDataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLPolyDataReader()
--
            reader = vtkPLYReader()
            reader.SetFileName(file_name)
            reader.Update()
            poly_data.DeepCopy(reader.GetOutput())
        elif ext == '.vtp':
            reader = vtkXMLPolyDataReader()
--
    reader = vtkPLYReader()
    reader.SetFileName(fileName)
    reader.Update()

    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(reader.GetOutputPort())
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLPolyDataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLpoly_dataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLpoly_dataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.vtp':
        reader = vtkXMLpoly_dataReader()
--
        reader = vtkPLYReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == ".vtp":
        reader = vtkXMLPolyDataReader()
