Apple Motion 3 - Manual (Page 345)

Chapter 4 Using the Timeline 345
Slipping Clips
Slip a clip when you want to use a different section of your clip, but you don’t want to
change the layer’s duration or where it appears in the Timeline. Slipping is only
possible after you have trimmed a clip.
For example, if you have a shot of a door opening that is 3 seconds long and you want
to trim it down to only 1 second, you can use the Slip function to select which second
section to use: the first second as the door leaves the jamb, the next second where it is
flying open, or the last second where it bangs against the wall.
Note: You can only slip a clip as far as the existing unused frames in the source media.
To slip a clip:
1 With the pointer over the clip, press and hold down the Option key.
The pointer turns into the slip pointer.
2 Drag the middle part of the colored bar left or right.
Dragging to the right replaces the frames with a section from later in the source
material, while dragging to the left uses frames from earlier in the clip.
Deleting Objects
Removing objects from your project can be just as important as adding them. Motion
provides three ways to remove an object from the Timeline.
Before After