Apple Motion 3 - Manual (Page 551)

Chapter 6 Keyframes and Curves 551
To apply the Before First Keyframe for a parameter:
m In the Keyframe Editor, open the Animation menu for the parameter you want to
change, then choose an item from Before First Keyframe submenu.
To apply the After Last Keyframe setting for a parameter:
m In the Keyframe Editor, open the Animation menu for the parameter you want to
change, then choose an item from After Last Keyframe submenu.
The following table describes the extrapolation options available in the Before First
Keyframe and After Last Keyframe submenus.
Extrapolation method Example Description
Constant (Default) The parameter remains at the
exact value of the first and last keyframes
in the extrapolated area.
Linear Extends the curve beyond the first and
last keyframes uniformly, along the
existing trajectory.
Ping Pong Copies the curve and repeats it,
alternating forward and backward.