About Frame-By-Frame Animation; About Layers In Animation - MACROMEDIA FLASH 8-USING FLASH Use Manual

Tweened animation is an effective way to create movement and changes over time while
minimizing file size. In tweened animation, Flash stores only the values for the changes
between frames.
To quickly prepare elements in a document for tweened animation, distribute objects to
layers. See "Distributing objects to layers" on page 253.
You can apply tweened animation to an object on a mask layer to create a dynamic mask. For
information on mask layers, see "Using mask layers" on page 268.

About frame-by-frame animation

Frame-by-frame animation changes the contents of the Stage in every frame and is best suited
to complex animation in which an image changes in every frame instead of simply moving
across the Stage. Frame-by-frame animation increases file size more rapidly than tweened
animation. In frame-by-frame animation, Flash stores the values for each complete frame. For
information on frame-by-frame animations, see "Creating frame-by-frame animations"
on page 264.

About layers in animation

Each scene in a Flash document can consist of any number of layers. As you animate, you use
layers and layer folders to organize the components of an animation sequence and to separate
animated objects so they don't erase, connect, or segment each other. If you want Flash to
tween the movement of more than one group or symbol at once, each must be on a separate
layer. Typically, the background layer contains static artwork, and each additional layer
contains one separate animated object.
When a document has several layers, tracking and editing the objects on one or two of them
can be difficult. This task is easier if you work with the contents of one layer at a time. Layer
folders help you organize layers into manageable groups that you can expand and collapse to
view only the layers relevant to your current task. See "Using layers" in Getting Started with
Flash.
About layers in animation 249