Apple Motion 2 Tutorials - Manual (Page 181)

Tutorial 4 Working With Particles 181
The Canvas should look similar to the image below.
With either of the color tags at the bottom of the Gradient Editor selected, a triangle-
shaped spread control appears between the two. The Gradient Editor works the same
way for shapes as it does for particles.
8 Click the spread control between the two color tags.
9 Set the Location value to 60 percent.
10 Save your project (press Command+S).
Now that the sky is in place, add the sun.