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Motion tweens
About tweened animation
A tween is an animation that is created by specifying a value for an object property in one frame and another value for
that same property in another frame. Flash calculates the values for that property in between those two frames. The
term tween comes from the words "in between".
For example, you can place a movie clip on the left side of the Stage in frame 1 of the Timeline, and then move that
movie clip to the right side of the Stage in frame 20. When you create a tween, Flash calculates all the positions of the
movie clip on Stage in between the two positions, right and left, that you specified. You end up with an animation of
the movie clip moving from the left side of the Stage to the right side, from frame 1 to frame 20. In each frame in
between, Flash moves the movie clip one 20th of the distance across the Stage.
The types of objects that can be tweened include movie clip, graphic and button symbols, and text fields. The properties
of these objects that can be tweened include the following:
•
2D X and Y position
•
3D Z position (movie clips only)
•
2D rotation (around the z axis)
•
3D X, Y, and Z rotation (movie clips only)
3D motion requires that the FLA file target ActionScript 3.0 and Flash Player 10 in the publish settings.
•
Skew X and Y
•
Scale X and Y
•
Color effects
Color effects include alpha (transparency), brightness, tint, and advanced color settings. Color effects can be
tweened only on symbols. To tween a color effect on text, convert the text to a symbol.
•
Filter properties (not including filters applied to graphic symbols)
A tween span is a group of frames in the Timeline in which an object on the Stage can have one or more properties
changed over time. A tween span appears in the Timeline as a group of frames in a single layer with a blue background.
These tween spans can be selected as a single object and dragged from one location in the Timeline to another,
including to another layer. Only one object on the Stage can be animated in each tween span. This object is called the
target object of the tween span.
A property keyframe is a frame within a tween span where you explicitly define one or more property values for the
tween target object. Each property you define has its own property keyframes. If you set more than one property in a
single frame, then the property keyframes for each of those properties reside in that frame. You can view each property
of a tween span and its property keyframes in the Motion Editor. You can also choose which types of property
keyframes to display in the Timeline from the tween span context menu.
In the preceding example of tweening a movie clip from the left side of the Stage to the right side from frame 1 to frame
20, frames 1 and 20 are property keyframes. You can use the Property inspector, the Motion Editor, the Transform
panel, or various tools in the Tools panel to define explicit values for properties you want to animate. You specify these
property values in the frames of your choosing, and Flash adds the required property keyframes to the tween span.
Flash interpolates the values for each of these properties in the frames in between the property keyframes you have
created.
Updated 5 March 2009
USING FLASH CS4 PROFESSIONAL
Timelines and Animation
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