Shape Tween Setup
Before we can create our tween we are going to need the
shapes that will be used to produce the tween effect. First,
create a simple rectangle like the one we have below, in frame 1
of your timeline.
Select frame 25 in the timeline window and insert a KeyFrame.
Select frame 50 and insert another KeyFrame. Notice that there
is a shaded area from frame 1 to 50. This is your "active" area
and the animation is going to occur within this area.
Changing Our Shapes
We want our shape to morph from one shape to another. For
contrast let's have our red box morph into a blue circle.
Select the middle frame, frame 25, and draw a big blue circle
on top of the existing red box, so that it is completely
covered. Using the Oval Tool in frame 25, hold shift, left-click
and drag to create a large blue circle. Your stage should now
look like this for frame 25.
Inserting the Shape Tween
In the timeline window, select any frame from 2-24 using
left-click. In the Properties window you will now see an option
to tween. It is currently set to none. From the Tween drop down
selector choose Shape.
Now insert another KeyFrame at frame 26. Left click
any frame from 27-49 and once again select the Shape Tween from
the Properties window.
If you have a dotted line, rather than a solid line in your
Timeline window, be sure that you followed the instructions up
to this point exactly.