Apple Motion 3 - Manual (Page 698)

698 Chapter 8 Working with Particles
For particle systems containing multiple cells, the Emitter HUD parameters
simultaneously modify the effect of each cell’s parameters relative to one another. This
means that for a particle system consisting of two cells with different scale values,
changing the scale in the HUD resizes both cells simultaneously. For example,
increasing the scale in the HUD by 200% does not change the scale of both cells to
200%, but resizes the cells relative to their original scale values.
For this reason, in emitters with multiple cells, the HUD parameters are displayed as
percentages. When you modify the parameters of a single cell, the cell parameters are
adjusted directly.
Birth Rate: A slider defines how many particles are created every second.
Life: A slider defines how long each particle remains onscreen (in seconds) before
disappearing from existence.
Scale: A slider defines the size of each particle, relative to the original size of the cell.
Emission Control: A graphical control that lets you modify several parameters.
 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.
 Emission Angle: Drag inside the emission control to change the direction in which
particles are emitted, inside the area defined by the Emission Range.
 Speed (2D only): Drag inside the emission control to shorten or lengthen the arrows
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 Angle): Restricts angles to 45 degree increments.
Original particle system Particle system scaled to 200%