Apple Motion 4 - Manual (Page 615)

As you increase the birth rate, more particles are created, forming a nearly unified column
of “smoke.” The particles move farther apart as they drift away from the emitter.
As you can see, a single object can be used to create a credible column of smoke rising
gently into the sky.
While the HUD controls are quite powerful, the Emitter and Particle Cell tabs in the
Inspector have many more parameters you can customize. For more information, see
Emitter and Cell Parameters .
Emitter HUD Parameters
The HUD contains the most frequently used emitter controls that are necessary to modify
a particle system’s size and shape. These parameters are a subset of those found in the
Emitter tab of the Inspector. In 2D projects, the Emitter HUD contains a group of sliders
and the emission control, which provides a visual way to manipulate three different
particle system parameters: Emission Range, Emission Angle, and Speed.
Emission Angle
(angle of arrow)
Emission Range
Emission Speed
(length of arrow)
2D Emitter HUD
615 Chapter 11 Working with Particles