#!/usr/bin/env python
import vtk

dr = vtk.vtkXMLPolyDataReader()
dr.SetFileName('doh.vtp')

box = vtk.vtkBox()
box.SetBounds(0, 0.65, -0.982, 0.984, -1.03, -0.302)

clip = vtk.vtkClipDataSet()
clip.SetInputConnection(dr.GetOutputPort())
clip.SetClipFunction(box)
clip.Update()
print clip.GetOutput()

dw = vtk.vtkXMLUnstructuredGridWriter()
dw.SetInputConnection(clip.GetOutputPort())
dw.SetDataModeToAscii()
dw.SetFileName('doh.vtu')
dw.Write()