PDF (adobe.com)

Example: Make a layer revolve in a circle

You can create an expression without using properties from other layers. For example, you can make a layer revolve in a perfect circle.

  1. Select a layer, press P to reveal its Position property in the Timeline panel, and Alt-click (Windows) or Option-click (Mac OS) the stopwatch to the left of the property name.
  2. Enter the following in the expression field: 
      [(thisComp.width/2), (thisComp.height/2)] + [Math.sin(time)*50, -Math.cos(time)*50]