Faux 3D Doorway

Edit the doorway with "Edit Path Mode"

Turning on edit path mode allows you to edit the source path (just click on the layer and select the path) that will create the doorway automatically.

Change the dimensions of the gate

Make the gate taller, wider, or deeper with separate sliders

Attach objects to the gate for a parallax effect

Pick whip a null's position to the "Inner Door Position" point control and get an automatic parallax effect