By tweening shapes, you can create an effect similar to morphing, making one shape appear to change into another shape over time. Flash can also tween the location, size, color, and opacity of shapes.

Tweening one shape at a time usually yields the best results. If you tween multiple shapes at one time, and want them to morph together, all the shapes must be on the same layer. Otherwise, for some effects, you should shape tween each shape on separate layers if you do not want them to affect each other. Each rectangle‹the curtain effect in the background and the rectangle on top ­ tweens on its own separate layer.

To apply shape tweening to groups, instances, or bitmap images, you must first break these elements apart (Modify > Break Apart). To apply shape tweening to text, you must break the text apart twice to convert the text to objects.

Note: To control more complex or improbable shape changes, you use shape hints, which control how parts of the original shape move into the new shape. For information, see the following section, Using Shape Hints with Shape Tweens.

To tween a shape:

1. Create a new file and call it shapetween.fla.
2. Select Frame 1 of Layer 1. This is where the animation will start.
3. Create a graphic with the Pen, Oval, Rectangle, Pencil, or Brush tool. For best results when you're starting out, the frame should contain only one drawing (such as a single oval shape).
4. Select Frame 10 of Layer 1 and create a second keyframe (F6).
5. Select the artwork on the Stage at Frame 10 and do one of the following:

• Modify the shape, color, opacity, or position of the artwork.
• Delete the artwork and place new artwork in the second keyframe (it should be a raw graphic drawing as well).

6. Select a frame in Timeline between Frame 1 and Frame 10.
7. In the Property inspector (Window > Properties > Properties), select Shape from the Tween pop-up menu.
8. Select an option for Blend:

• Distributive creates an animation in which the intermediate shapes are smoother and more irregular.
• Angular creates an animation that preserves apparent corners and straight lines in the intermediate shapes.

Note: Angular is appropriate only for blending shapes with sharp corners and straight lines. If the shapes you select do not have corners, Flash reverts to distributive shape tweening.

Using Shape Hints with Shape Tweens
To control more complex or improbable shape changes, you can use shape hints. Shape hints identify points that should correspond to starting and ending shapes. For example, if you are tweening the letter M into the letter N, you can use a shape hint to mark corner of the letter's shape. Then, instead of the letters becoming a jumble of lines while the shape change takes place, each letter remains recognizable and changes separately during the shift.

To use shape hints:

1. Create a shape tween (see the previous section, Creating Shape Tweens).
2. Select Frame 1 of the layer with the animation on the Timeline.
3. Select Modify > Shape > Add Shape Hint.
4. Move the shape hint to an edge or corner that you want to mark.
5. Select the next keyframe in the tweening sequence.
6. Move the shape hint to the edge or corner in the ending shape that should correspond to the first location you marked.

Repeat this process to add additional shape hints. New hints appear with the letters that follow (b, c, and so on).

The SWF files animate the letter M into the letter N. The top SWF file does not use shape hints to morph the two letters, while the bottom SWF file uses shape hints to improve the morphing. Refer to the sample file shape_hints.fla, which is part of the animation_samples.zip archive that accompanies this article.

Shape hints contain letters (a through z) for identifying which points correspond in the starting and ending shape. You can use up to 26 shape hints. Shape hints are yellow in a starting keyframe, green in an ending keyframe, and red when within a fill area or outside the shape (Flash ignores red shape hints).

For best results when tweening shapes, follow these guidelines:

• In complex shape tweening, create intermediate shapes and tween them instead of just defining a starting and ending shape.
• Make sure that shape hints are logical. For example, if you're using three shape hints for a triangle, they must be in the same order on the original triangle and on the triangle to be tweened. The order cannot be abc in the first keyframe and acb in the second.
• Shape hints work best if you place them in counterclockwise order beginning at the top left corner of the shape.

Creating Frame-by-Frame Animations
A frame-by-frame animation changes the contents of the Stage in every frame and is best suited to a complex animation in which an image changes in every frame instead of simply moving across the Stage. This type of animation increases the file size more rapidly than tweened animation because Flash stores the values for each keyframe.

To create a frame-by-frame animation, you define each frame as a keyframe and create a different (typically modified) image for each frame. Each new keyframe on a layer typically contains the same contents as the keyframe preceding it because the contents of a frame are copied to the next keyframe when you select a frame and press F6. By selecting a frame and pressing F6, you can modify each new keyframe in the animation incrementally. The bee's wing moves only slightly so that a frame-by-frame animation was used to move the wing very slightly on sequential frames.

Often, you use the onion skin feature to view incremental changes between each keyframe. A motion tween has been applied to the lemur's arm and head. The onion skin tool enables you to view multiple frames of the animation at once.

To turn on onion skinning, click the Onion Skin or Onion Skin Outlines button near the bottom of the Timeline. Drag the markers above the Timeline to view multiple frames at once. The onion skin outlines are enabled for an animation on the Stage.

To create a frame-by-frame animation:

1. Create a new file and call it framebyframe.fla.
2. Select Frame 1 of Layer 1. This is where the animation will start.
3. Create a graphic with the Pen, Oval, Rectangle, Pencil, or Brush tool. You can also paste graphics from the Clipboard or import a file (such as an Adobe Illustrator illustration).
4. Select the next frame on Layer 1 and create a second keyframe (F6). The contents of Frame 2 are the same as Frame 1 at this time.
5. Alter the contents of this frame on the Stage to develop the next increment of the animation. You might select the graphic and move it a couple pixels to the right, add some new lines, or bend a line on a shape.
6. To complete your frame-by-frame animation sequence, repeat Steps 4 and 5 until you've built the motion you want.
7. To test the animation sequence, select Control > Play or Control > Test Movie.

Editing Your Animations
In Flash 8 you can use various tools to edit your animations, such as commands to insert frames, modify keyframes, onion-skinning tools, and the ability to move your animations around timelines.

After you create a frame or a keyframe, you can move it elsewhere in the active layer or to another layer, remove it, and make other changes. Only keyframes are editable. You can view tweened frames, but you can't edit them directly. To edit tweened frames, you change one of the defining keyframes or insert a new keyframe between the beginning and ending keyframes. You can drag items from the Library panel onto the Stage to add the items to the current keyframe.

To display and edit more than one frame at a time, use onion skinning, covered next.

• Flash Animation Learning Guide (Part I)

• Figure 1
• Figure 2
• Figure 3
• Figure 4
• Figure 5