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 second in the series, After Effects Apprentice 08: Nesting and Precomposing.
Precomposing allows you to select one or more layers, and create a new composition for them to reside in. This new precomp is then automatically nested—in other words, it becomes a single layer—in the original composition. This technique is the most comprehensive approach to grouping, as anything you do to resulting nested layer—including changing its opacity or applying effects—will affect the grouped layers.
In addition to grouping layers, intelligent use of nesting and precomposing to build a hierarchy of comps allows you to rewire the rendering order (order of operations, such as transformations and effects) for After Effects, as well as reuse common elements in multiple compositions, which in turn makes it much easier to accommodate client changes.
Watch the entire course: After Effects Apprentice 08: Nesting and Precomposing.