        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == ".stl":
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
    reader = vtkOBJReader()
    reader.SetFileName(fileName)
    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(reader.GetOutputPort())
    actor = vtkActor()
    actor.SetMapper(mapper)
--
            reader = vtkOBJReader()
            reader.SetFileName(file_name)
            reader.Update()
            poly_data.DeepCopy(reader.GetOutput())
        elif ext == '.stl':
            reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == '.stl':
        reader = vtkSTLReader()
--
        reader = vtkOBJReader()
        reader.SetFileName(file_name)
        reader.Update()
        poly_data = reader.GetOutput()
    elif extension == ".stl":
        reader = vtkSTLReader()
