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248 Chapter 11: Space Warps and Particle Systems
Basic Parameters rollout > D isplay Icon group
The emitter specifies the location where particles
are generated in the scene. It has a geometry you
can display in viewports, but it isn’t renderable.
The emitter is displayed as a rectangle with a
vector pointing out of one side. The vector shows
the direction in which the system emits particles.
You set emitter parameters on the particle system’s
Basic Parameters rollout, in the Display Icon
group.
Width and Length—You implicitly set the initial
value of these parameters when you drag in a
viewport to create the emitter. You can adjust the
values on the rollout.
Thespaceoccupiedbytheparticlesystematany
given time is the result of a combination of its
initial parameters (such as size of the emitter, and
speed and variation of emission) and any space
warps that have been applied.
Emitter Hidden—Hides the emitter in viewports.
When off, the emitter is displayed in viewp orts.
The e mitter is never rendered. Default=off.
Particle Generation rollout > Particle Motion
group
Specifies the number, size, and motion of particles.
Speed—Thespeedoftheparticleatbirth,inunits
per frame.
Variation—Applies a percentage of variation to the
speed of emission for each part icle.