Download the sample files here.
Shape tweening is similar to morphing. Whith shape tweening, we make one shape appear to change into another shape over time.
To tween a shape, follow these direcitons.
1. Click a layer name to make it current.
2. Select an empty keyframe in the layer, and create a object. In this example, I created a rectangle.
3. Create a second keyframe where you want the animation to end.
4. In the final keyframe, delete the existing object and create a circular object.
5. If the Properties inspector is not visible, choose Window > Properties.
6. Select the first key frame, and select Shape from the Tween pop-up menu in the Properties inspector.
This is all you need to do! Test the movie.