[farshizzo]

Here is an example that applies a clip plane to a model and updates it every frame so that the plane is relative to the current viewpoint. Let me know if this isn't what you were asking for.

import viz
viz.go()

viz.add('ball.wrl',pos=(0,1.5,2))
model = viz.add('gallery.ive')

import vizact

def UpdateClipPlane():

	mat = viz.MainView.getMatrix()
	mat.preEuler(0,0,90)

	p = viz.Plane()
	p.setQuat(mat.getQuat())
	p.setPos(mat.getPosition())
	model.clipPlane(p)

vizact.onupdate(viz.PRIORITY_LAST_UPDATE,UpdateClipPlane)