Apple Motion 4 - Manual (Page 663)

To turn the system into 3D particles
1 In the Emitter Inspector, select the 3D checkbox.
3D checkbox
2 If your project does not contain a camera, click the New Camera button in the Toolbar.
If your project is a 2D project, a dialog appears asking if you want to switch your 2D
groups to 3D.
3 Click Switch to 3D.
A camera is added to the project, and your layers are turned into 3D layers.
4 In the 3D View tools (in the upper-right corner of the Canvas), drag the Orbit tool (the
center tool).
Pan tool
Orbit tool
Dolly tool
As the camera rotates, you can see that the particles are emitted in Z space.
663 Chapter 11 Working with Particles