Rotate one axis towards camera

Hi guys. I'm working on building a 3d model of a stage scaffolding for lights
inside after effects. The poles holding it up are actually planes which I'd like
to rotate towards the camera so that they appear to be cylinders. However, I
need only the y axis to rotate so that the poles stay rooted to the ground. Does
anyone have any ideas as to a simple expression to achieve this?

Thanks,

Choose Transform -> Auto-Orient -> Orient Towards Camera.

- Jonas Hummelstrand

Dan Ebberts came up with a great solution for orienting in one axis. Apply the
following expression to the Y rotation property:

      delta = toWorld(anchorPoint) - thisComp.activeCamera.toWorld([0,0,0]);
      radiansToDegrees(Math.atan2(delta[0],delta[2]))





you'll find more details here:
 <http://www.motionscript.com/design-guide/auto-orient-y-only.html>