Adobe® Flash® CS4 Professional provides several ways to create animation and special effects. Each method provides you with different possibilities for creating engaging animated content.

Flash supports the following types of animation:

Motion tweens

Use motion tweens to set properties for an object, such as position and alpha transparency in one frame and again in another frame. Flash then interpolates the property values of the frames in between. Motion tweens are useful for animation that consists of continuous motion or transformation of an object. Motion tweens appear in the Timeline as a contiguous span of frames that can be selected as a single object by default. Motion tweens are powerful and simple to create.

Classic tweens

Classic tweens are like motion tweens, but are more complex to create. Classic tweens allow for some specific animated effects not possible with span-based tweens.

Inverse Kinematics poses

Inverse kinematic poses allow you to stretch and bend shape objects and link groups of symbol instances to make them move together in naturalistic ways. You can position the shape object or linked instances in different ways in separate frames, and Flash interpolates the positions in the frames in between.

Shape tweens

In shape tweening, you draw a shape at one specific frame in the Timeline, and change that shape or draw another shape at another specific frame. Flash then interpolates the intermediate shapes for the frames in between, creating the animation of one shape morphing into another.

Frame-by-frame animation

This animation technique lets you specify different art for each frame in the Timeline. Use this technique to create an effect that is like the frames of a film being played in rapid succession. This technique is useful for complex animation where the graphic elements of each frame must be different.

The following video tutorial provides further explanation of the different types of animation: Understanding tweens (2:36).

The frame rate, the speed the animation is played at, is measured in number of frames per second (fps). A frame rate that’s too slow makes the animation appear to stop and start; a frame rate that’s too fast blurs the details of the animation. A frame rate of 24 fps is the default for new Flash documents and usually gives the best results on the web. The standard motion‑picture rate is also 24 fps.

The complexity of the animation and the speed of the computer playing the animation affect the smoothness of the playback. To determine optimum frame rates, test your animations on a variety of computers.

Because you specify only one frame rate for the entire Flash document, set this rate before you begin creating animation.

Flash distinguishes tweened animation from frame-by-frame animation in the Timeline by displaying different indicators in each frame that contains content.

The following frame content indicators appear in the Timeline:

• A span of frames with a blue background indicates a motion tween. A black dot in the first frame of the span indicates that the tween span has a target object assigned to it. Black diamonds indicate the last frame and any other property keyframes. Property keyframes are frames that contain property changes explicitly defined by you. You can choose which types of property keyframes to display by right-clicking (Windows) or Command-clicking (Macintosh) the motion tween span and choosing View Keyframes > type from the context menu. Flash displays all types of property keyframes by default. All other frames in the span contain interpolated values for the tweened properties of the target object.

  

• A hollow dot in the first frame indicates that the target object of the motion tween has been removed. The tween span still contains its property keyframes and can have a new target object applied to it.

  

• A span of frames with a green background indicates an inverse kinematics (IK) pose layer. Pose layers contain IK armatures and poses. Each pose appears in the Timeline as a black diamond. Flash interpolates the positions of the armature in the frames in between poses.

  

• A black dot at the beginning keyframe with a black arrow and blue background indicates a classic tween.

  

• A dashed line indicates that the classic tween is broken or incomplete, such as when the final keyframe is missing.

  

• A black dot at the beginning keyframe with a black arrow and a light green background indicates a shape tween.

  

• A black dot indicates a single keyframe. Light gray frames after a single keyframe contain the same content with no changes. These frames have a vertical black line and a hollow rectangle at the last frame of the span.

  

• A small a indicates that the frame is assigned a frame action with the Actions panel.

  

• A red flag indicates that the frame contains a label.

  

• A green double slash indicates that the frame contains a comment.

  

• A gold anchor indicates that the frame is a named anchor.

  

Each scene in a Flash document can consist of any number of Timeline layers. Use layers and layer folders to organize the contents of an animation sequence and separate animated objects. Organizing them in layers and folders prevents them from erasing, connecting to, or segmenting each other when they overlap. To create animation that includes tweened movement of more than one symbol or text field at once, place each object on a separate layer. You can use one layer as a background layer to contain static artwork and use additional layers to contain one separate animated object.

When you create a motion tween, Flash converts the layer containing the object you selected to tween into a tween layer. The tween layer has a tween icon next to the layer name in the Timeline.

If other objects are present on the same layer as the tweened object, Flash adds new layers above or below the original layer as needed. Any objects that existed below the tweened object on its original layer move to a new layer below the original layer. Any objects that were above the tweened object on its original layer move to a new layer above the original layer. Flash inserts these new layers between any pre-existing layers in the Timeline. In this way Flash preserves the original stacking order of all the graphic objects on the Stage.

A tween layer can contain only tween spans (contiguous groups of frames containing a tween), static frames, blank keyframes, or empty frames. Each tween span can contain only a single target object and an optional motion path for the target object. Because you cannot draw in a tween layer, create additional tweens or static frames on other layers and then drag them to the tween layer. To place frame scripts on a tween layer, create them on another layer and drag them to the tween layer. A frame script can only reside in a frame outside the motion tween span itself. In general, it is best to keep all frame scripts on a separate layer that contains only ActionScript.

When a document has several layers, tracking and editing the objects on one or more of them can be difficult. This task is easier if you work with the contents of one layer at a time. To hide or lock layers you are not currently working on, click the Eye or Lock icon next to the layer name in the Timeline. Using layer folders can help you organize layers into manageable groups.

Flash automatically moves an object to its own tween layer when you apply a motion tween to the object. However, you can also distribute objects to their own separate layers yourself. For example, you can choose to distribute objects yourself when you are organizing content. Manual distribution is also useful for applying animation to objects while maintaining precise control over how they move from one layer to another.

When you use the Distribute To Layers command (Modify > Timeline > Distribute To Layers), Flash distributes each selected object to a new, separate layer. Any objects that you don’t select (including objects in other frames) are preserved in their original layers.

You can apply the Distribute To Layers command to any element on the Stage, including graphic objects, instances, bitmaps, video clips, and broken-apart text blocks.

The following articles are available about working with animation in Flash:

• Creating a simple animation in Flash (Adobe.com)

• Animation Learning Guide for Flash CS4 Professional (Adobe.com)

• Motion migration guide for Flash CS4 Professional (Adobe.com)

• Creating animation in ActionScript 3.0 (Adobe.com)