Emitter HUD controls
Adjust an emitter using the controls in the Emitter HUD:
Birth Rate: A slider that defines how many particles are created every second.
Life: A slider that defines how long each particle remains onscreen (in seconds) before disappearing from existence.
Scale: A slider that defines the size of each particle, relative to the original size of the cell.
Emission Range: A slider that defines the angle at which particles are emitted.
Emission control (not labeled): A circular graphical control that lets you modify several parameters simultaneously, described below:
Emission Range (2D only): Drag the two points on the outer ring of the graphical emission control to define the range of degrees at which particles are generated. In other words, the Emission Range parameter defines the size of the “slice” of the pie graph that the particles fill when generated. This graphical control adjusts the same parameter as the Emission Range slider.
Emission Angle (2D only): Drag the blue arrows clockwise or counterclockwise to change the direction in which particles are emitted (within the angle defined by the Emission Range control).
Emission Speed (2D only): Drag the blue arrows outward or inward to define how quickly particles move away from the emitter.
Use the following modifier keys to more precisely manipulate the graphical emission control in the HUD:
Shift (while adjusting Emission Angle): Restricts angles to 45-degree increments.
Shift (while adjusting Emission Range): When working with a 2D emitter, restricts to 22.5-degree increments.
Command: When working with a 2D emitter, adjusts Emission Angle only.
Option: When working with a 2D emitter, adjusts Emission Speed only.
Emission Latitude/Emission Longitude control (not labeled, 3D only): When using a 3D particle emitter (when the 3D checkbox is selected in the Emitter Inspector), the spherical emission control of the HUD lets you modify the Emission Latitude and Emission Longitude parameters.
Drag the sphere in the center of the circle to modify the emission direction (in degrees latitude and longitude) of the particles. You can also enter specific values in the Emitter Inspector.
Drag the Emission Range slider (above the sphere) to define the range of degrees at which particles are generated. In other words, this control defines the size of the cone that the particles fill when generated in 3D space.