Apple Motion 3 - Manual (Page 515)

Chapter 6 Keyframes and Curves 515
Combining Behaviors and Keyframes
Because it is possible to add keyframes to an object that may already have a behavior
(or many behaviors) applied, it is possible that these two methods could conflict. For
example, you might apply a Throw behavior toward the upper left, and at the same
time add keyframes that instruct the object to move to the right. Now what?
The way Motion handles this sort of conflict is that the instructions are added together,
giving you a combination of the two sets of instructions. In the above example, the
object would move toward the upper left, but it won’t get as far, because the
keyframes are pushing it in an opposing direction.
The larger the Throw velocity rate, the more it overpowers the keyframes, and vice
versa.
Behavior motion path Keyframe motion path
Combined motion path