Apple Motion 2 Tutorials - Manual (Page 225)

Tutorial 5 The Replicator 225
To align the angles of the objects to their related arms:
m Turn on the Align Angle checkbox.
Now, the objects are aligned with each arm of the burst to which they are attached,
giving the burst rotational symmetry.
Now, shrink the Burst so it occupies an area just around the center of the Canvas.
To shrink the Burst pattern:
1 In the Inspector, change Radius to 45.
2 Save your project (press Command+S).