Shape Tweens are used to change the size, location, color, and/or transparency of vector-based shapes. NOTE: Shape Tweens can NOT be used to re-size text that has been typed directly into Flash. Motions Tweens must be used to alter the size, location, etc. of text in Flash. Attached Screenshots: First and last frames of a basic Shape Tween of a circle vector shape TIP: To know if you have created a Tween correctly, look for the solid arrow between the first and last Keyframes of your Tween. Flash will create a broken line between the Keyframes if your Tween was not created correctly.
Quicktime Tutorial: Learn how to create basic Shape Tweens in Flash