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Age Test 211
Age Test
Particle View (page 2–125) >ClickAgeTestinaneventor
add Age Te st to the particle system and then select it.
Age Test lets the particle system check whether
a specific amount of time has passed since the
start of the animation, or how long a particle has
existed, or how long a particle has been in the
current event, and branch accordingly.
Inter face
The user interface appears in the parameters panel,
ontherightsideoftheParticleViewdialog.
The first interface element is a drop-down list
that lets you choose the type of age to test.
Default=Part icle Age.
•
Absolute Age—Te s t s t h e c u r rent f r ame nu mb e r
in the animation.
•
Par ticle Age—Tests the current age of each
particleinframes.Thisisthedefaulttesttype.
•
Event Age—Tests t he c u r rent d u r a t i o n o f t h e
current event in f r ames.
Test True if Par ticle Value—Lets you specify whether
the test passes particles on to the next event if the
age test succeeds or fails. Default=Is Greater Than
Te s t Va lue
By default, Age Test returns True if the value tested
for exceeds the Test Value quantity, but you can
alternatively choose Is Less T han Test Value. For
example, if you use the Absolute Age test ty pe and
setTestValue=60andVariation=0,andchooseIs
Less Than Test Value, then particles w ill move to
the next event only until fr ame 60. Af ter frame 60,
any remaining particles stay in the current event
unless another test returns True.
Test Value—The specific frame number, particle
age (in frames), or event durat ion (in frames) to
test for. Default=30.
This value cannot be animated.
Variation—The number of frames by w hich the
value tested for can vary randomly. Default=5.
This value cannot be animated.
To obtain the actual test value for each particle, the
system multiplies the Variation value by a random
number b e tween -1.0 and 1.0, and then adds the
result to the Test Value setting. For example, if Test
Va lue=300 and Variation=10, then tested value for
each particle would be between 290 and 310.
Subframe S ampling—Turningthisonhelpsavoid
particle "puffing" when passing particles to the
next event by testing the time at a much higher
subframe resolution (that is, throughout each
frame), rather than using the relatively coarse
frame resolution. Default=on.
"Puffing" is the effect of creating separ ate "puffs"
or clusters of particles, rather than a continuous
stream.
Turn off Subframe Sampling to cause the test to be
executed exactly at frame times.