[Jeff]

Here's an example. Use the left and right arrow keys to move the box:

'''
Move the clip box left and right
with the arrow keys
'''

import viz
import vizact
import vizshape
import vizinfo
viz.go()

vizinfo.InfoPanel()

class MovingClipBox():
	def __init__(self,node,center,size):
		
		self.node = node
		self.x,self.y,self.z = center
		self.sx,self.sy,self.sz = [ v / 2.0 for v in size ]
		self.applyClipBox()	
		self.box = vizshape.addBox(size=size,pos=center,color=viz.RED,lighting=False)
		self.box.polyMode(viz.POLY_WIRE)

	def applyClipBox(self):
		
		self.node.clipPlane([1,0,0,self.x-self.sx],num=0)
		self.node.clipPlane([-1,0,0,-self.x-self.sx],num=1)
		self.node.clipPlane([0,1,0,self.y-self.sy],num=2)
		self.node.clipPlane([0,-1,0,-self.y-self.sy],num=3)
		self.node.clipPlane([0,0,1,self.z-self.sz],num=4)
		self.node.clipPlane([0,0,-1,-self.z-self.sz],num=5)
		
	def getBoxCenter(self):
		return [self.x,self.y,self.z]

	def setBoxCenter(self,center):
		self.x,self.y,self.z = center
		self.applyClipBox()
		self.box.setPosition(center)
		
viz.clearcolor(viz.GRAY)
vizshape.addGrid(color=[0.2]*3)
model = viz.add('logo.osgb')

expand = vizact.sizeTo([3,3,3],speed=0.5)
shrink = vizact.sizeTo([1,1,1],speed=0.5)
model.runAction(vizact.sequence(expand,shrink,viz.FOREVER))
model.runAction(vizact.spin(0,1,0,20,viz.FOREVER),pool=1)
				
BOX_CENTER = [0,2,0]
BOX_SIZE = [2,2,2]
movingClipBox = MovingClipBox(model,center=BOX_CENTER,size=BOX_SIZE)

import vizcam
vizcam.PivotNavigate(center = BOX_CENTER, distance = 10.0)

def updateClipBox():
	
	x_change = 0
	if viz.key.isDown(viz.KEY_LEFT):
		x_change -= 0.01
	elif viz.key.isDown(viz.KEY_RIGHT):
		x_change += 0.01
	if x_change != 0:
		center = movingClipBox.getBoxCenter()
		center[0] += x_change
		movingClipBox.setBoxCenter(center)

vizact.onupdate(0,updateClipBox)