The three most recent installments of Chris and Trish Meyer’s After Effects Apprentice series have covered three different approaches to grouping layers in After Effects. Each approach has its own strengths and weaknesses; mastering all three means you can choose the right approach for a particular task—or combine them for the ultimate in power and flexibility. Here’s an overview from the first in the series, After Effects Apprentice 07: Parenting.
Parenting allows you to attach an entire layer to another. The child layer keeps its own animation, which is then also affected by the position, rotation, and scale of the parent layer (note that effects and opacity are not passed from the parent to its children). For example, you can attach several layers to one parent, reposition just the parent, and all of the children will move as well. The same goes for scaling the parent: All of the children will be scaled by the same amount, keeping their same relative sizes and positional offsets. A parent can have multiple children, and you can set up parent/child chains where a layer in the middle is both a parent and a child. All of the layers stay in the current composition.
Watch the entire course: After Effects Apprentice 07: Parenting