Apple Motion 4 - Manual (Page 737)

In addition to creating a more graceful animation, changing the Spread value can also
dramatically change the appearance of the pattern.
5 Set Opacity to the lowest value you want the elements to become in the animation.
In this example, Opacity is set to 0.
Each element fades from 100% opacity to 0% opacity over the pattern for the duration
of the Sequence Replicator behavior.
Note: If the elements already contain some transparency, they fade from their original
opacity value to 0%.
6 Increase the Scale value. In this example, Scale is set to 190%.
737 Chapter 12 Using the Replicator