Creating a Game Menu and a Particles Effect: An Angry Birds-like Game, Part II - Learn GameSalad for iOS: Game Development for iPhone, iPad, and HTML5 - page 205

Here you can define the speed and direction of the particles that you spawn as
well as their origins. This tab contains six setting parameters:
 Emitter Offset x: This parameter offsets the position on the x-
axis for the origin of the particles compared to the center of
the actor that has the particles behavior.
 Emitter Offset y: This parameter offsets the position on the y-
axis for the origin of the particles compared to the center of
the actor that has the particles behavior.
 Direction: Defines the direction of the spawned particles.
 Relative to: You can choose if you want the direction to be
relative to the actor or to the scene. For example, if you select
270 degrees for the direction relative to the scene, it will
always go down, whatever the position of the actor. If you
select 270 degrees for the direction relative to the actor, if will
go to the bottom of the actor, which will depend on the
rotation of the actor.
 Affected by gravity: If you have defined the scene gravity,
check this box if you want your particles to be affected by the
gravity.
 Speed: Enter a value to define the speed of the particles.
Size
The Size tab of the Particles behavior is shown in Figure 7-7.
Figure 7-7. Size tab of the Particles behavior
The Size tab defines the size of the particles, a start size, and a target size to be
reached within a specified time. The parameters are: