You can automatically orient 3-D layers toward the camera, and set up the camera to track a particular subject. Any 2-D layers in the composition are not affected by the camera and lighting effects. Keyboard commands let you switch among top, front, back, right, left, bottom, camera and up to three custom views. You can get multiple simultaneous views of the scene by setting up additional composition windows, but there's no automatic dual view or quad view mode. After Effects' new parenting functions work similarly to those in 3-D graphics programs, allowing you to define one layer as the parent or child of others.
Expressions provide a more-powerful way to define relations between layers.
It lets you intelligently link a property of one layer to a property of another, so that one layer's motion is defined by another according to rules that you've specified. For example, if you have a large gear on one layer and a small gear on the other, you can enter an expression that causes the small gear to rotate twice for each single rotation of the big gear. If you later change the big gear's rotation, the small gear's rotation adjusts automatically. You can also link unlike properties, so that one layer's position affects another layer's rotation, or one layer's opacity controls another layer's size. You can define basic expressions using the pick whip and popup menus, or use JavaScript to create complex expressions.