If I understood correctly, it should be possible to use a clip plane for this; perhaps this post of mine could help.
Another possibility could be to use a ScissorEffect, as in the following code:
from panda3d.core import *
from direct.showbase.ShowBase import ShowBase
from direct.interval.IntervalGlobal import LerpScaleInterval, Sequence
class Panda3DApp(ShowBase):
def __init__(self):
ShowBase.__init__(self)
cm = CardMaker("square")
cm.set_frame(-1., 1., -1., 1.)
cm.set_has_normals(False)
square_node = cm.generate()
square = self.aspect2d.attach_new_node(square_node)
scissor_controller = self.aspect2d.attach_new_node("scissor_controller")
square.set_scissor(scissor_controller, Point3(-1., 0., -1.), Point3(1., 0., 1.))
scale1 = (1., 1., .01)
lerp_interval1 = LerpScaleInterval(scissor_controller, 1., scale1)
scale2 = 1.
lerp_interval2 = LerpScaleInterval(scissor_controller, 1., scale2)
self.sequence = Sequence(lerp_interval1, lerp_interval2)
self.sequence.loop()
app = Panda3DApp()
app.run()Note that I’m not entirely sure if a scissor region is supposed to be controlled like this, but it seems to work.