9

Spawn Test 231
Inter face
The user interface appears in the parameters panel,
ontherightsideoftheParticleViewdialog.
In the context of Spawn, a parent is the original
particle from which new particles ar e spawned.
Spawn R ate And Amo unt group
Use these settings to specify how often particles
aretospawn,themeasurementsystemtouse,
andothervaluesrelatedtohowmanyparticles
are spawned.
Once—Particles spawn one time only. For each
existing particle, one new one is born.
Delete Parent—When on, deletes each original
particle from which a new one is spawned.
Available only w ith the Once option.
Per S econd—Lets you specify a number of particles
to sp awn every second. For example, if you use the
default Rate setting of 10.0, at 30 fps a new p article
is born every three frames.
Rate—The number of particles to spawn per
second. Avai lable only w ith the Per Second option.
By Travel Distance—Lets you spaw n new particles
at regular intervals over the path of a moving
parent particle.
Step Size—Thesystemspawnsanewparticleevery
time the parent moves this distance, in system
units.
Spawnable—The percent age of particles in the
current event that will spawn new particles. This is
determined once for each par ticle, when it enters
the event. However, the parameter is animatable.
Default=100.0.
For values other than 100.0, Spawnable uses a
randomized selec tion process, which is affected
by the Uniqueness Seed va lue. For example,
w ith five parent particles, Offspring # =1, and
Spawnable=80.0, you might get any number of
spawned particles between two and five. The
average per spawning would be four, however.
Offspring # —The number of new part icles the
system creates f rom each p arent particle for each
spawning event. Default=1.
Variation—TheamountbywhichtheOffspring#
value can vary ra ndomly. Default=0.0.
To obtain the actual test value for each particle, the
system multiplies the Variation value by a random
number between -1.0 and 1.0, and then applies the
result as a percentage of the Offspring # setting.