Perhaps the following code will be helpful. It seems to get a bit tricky when other nodes are partially clipped or are in line with the node that is always drawn:
Code:
import viz
viz.go()
viz.MainWindow.clip(10,1000)
ball = viz.addChild('beachball.osgb',pos=[0,1.8,4])
ball.disable(viz.ADJUST_AUTO_CLIP)
ball.disable(viz.DEPTH_TEST)
ball.drawOrder(10)
ball2 = ball.copy(pos=[0.5,1.8,4])
ball3 = ball.copy(pos=[-0.5,1.8,4])
ball4 = ball.copy(pos=[0,1.8,2])
ball5 = ball.copy(pos=[0,1.8,5])
piazza = viz.addChild('piazza.osgb')