how to "spin/spinto" an rectangular around its center or edge?

[znchb]

Please see the program below, I build an rectangular using polygon, and I want to make it spin around its Center point or around its Edge Line of rectangular ?
Is there anyone would like to help me?
Thank you very much!

import viz
import vizact
viz.go()
viz.clearcolor(viz.WHITE)
bg = viz.add('tut_ground.wrl')
pos = bg.getPosition()
viz.MainView.setPosition(pos[0],pos[1]+5,pos[2]-20)
A = [pos[0]-2, pos[1]+8, pos[2]+10 ]
B = [pos[0]+2, pos[1]+8, pos[2]+10 ]
C = [pos[0]+2, pos[1]+4, pos[2]+10 ]
D = [pos[0]-2, pos[1]+4, pos[2]+10 ]
viz.startlayer(viz.POLYGON)
viz.vertex(A)
viz.vertex(B)
viz.vertex(C)
viz.vertex(D)
Rectangular = viz.endlayer()
Rectangular.color(viz.RED)
#make it spin/spinto
#Rectangular.addAction(vizact.spinto(0,0,1, 180, 30))
Rectangular.addAction(vizact.spin(0,0,1, 90))
#---- How to make it spin around the Center of the rectangular ?-------
#---- or how to make it spin around the Edge Line of rectangular ? -----

[znchb]

Is there anyone can help me? I really need to solve this problem, which is one function of my project.
I will be very appreciated.

[farshizzo]

You should create the rectangle so that it is centered around the axis you want it to rotate about. Instead of adding the position to the vertex positions, specify the vertices so they are centered about the origin (0,0,0), and then add the position to the entire model using the Rectangular.setPosition command.