Summary

We covered a lot of material for something that appears to be a simple interface component layers. It's hard to say that layers aren't primarily for visual stacking because that's exactly how they work. Remember that Drawing Objects and groups (or, better yet, putting objects in the Library) also lets you stack them (within one layer). However, creating separate layers is sometimes more convenient.

Layers are useful for more than creating the layering effect, however. The number-one rule of motion tweens is that only one object (an instance of a symbol) be tweened per layer. If you want more things to animate, you have to put each one in its own layer.

This hour we discussed layer properties, how entire layers can be hidden or locked at will, and how the Show Layer as Outlines feature provides a way to view the contents of any layer as an outline. Those properties are accessible right in the Timeline.

The Guide Layer property excludes an entire layer from export but keeps it in the source Flash file for any purpose, including registration. Motion Guide layers let us pair up the Guide layer with a motion tween (in the lower layer) to follow a drawn path. Finally, Mask layers (paired with a Masked layer) give us a way to hide all portions (except those we indicate) of another layer.