Separate XYX

Separate XYX

The Graph Editor reveals the problem. The red X graph
shows an unsteady horizontal motion due to the eases. The
problem is that the eases should be applied only to the
vertical Y dimension, whereas the X animation travels at a
constant rate.
New to After Effects CS4 is the ability to animate X and Y
(or, in 3D, X, Y, and Z) animation curves separately. This
allows you to add keyframes for one dimension only at a
given point in time, or to add keyframes in one dimension
at a time.
Select Position and click Separate Dimensions . Where
there was a single Position property, there are now two
marked X Position and Y Position. Now try the following:

1. Disable the Graph Editor Set toggle for Y Position so
that only the red X Position graph is displayed.
2. Select the middle three X Position keyframes—you can
draw a selection box around them—and delete them.
3. Select the two remaining X keyframes and click the
Convert Selected Keyframes to Linear button .
Now take a look in the Composition viewer—the motion is
back to linear, although the temporal eases remain on the
Y axis. Not only that, but you cannot redraw them as you
did before; enabling Separate Dimensions removes this
ability.
Instead, you can create them in the Graph Editor itself.
1. Enable the Graph Editor Set toggle for Y Position, so
both dimensions are once again displayed.
2. Select the middle Y Position keyframe, and you’ll notice
two small handles protruding to its left and right. Drag
each of these out, holding the Shift key if necessary to
keep them fl at, and notice the corresponding change
in the Composition viewer (Figure 2.7).

3. Select the fi rst and last Y Position keyframes and click

Easy Ease; the handles move outward from each keyframe

without affecting the X Position keyframes.

4. Drag the handles of the fi rst and last Y Position keyframes

as far as they will go (right up to the succeeding

and preceding keyframes, respectively).

Preview the result and you’ll see that you now have the

beginnings of an actual bouncing ball animation; it’s just a

little bit too regular and even, so from here you will give it

your own organic touch.