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Age Test 207
Age Test
Particle View (page 2– 121) > C lick Age Test in an event or
add Age Test to the particle system and then select it.
Age Test lets the part icle system check whether
a specific amount of time has passed since the
start of the anim ation, 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—Tes t s t h e c u r r e nt f r a m e nu mb e r
in the animation.
•
Par ticle Age—Tests the current age of each
particleinframes.Thisisthedefaulttesttype.
•
Event Age—Te s t s t he c u r r e nt du r a t ion o f t h e
current event in frames.
Test True if Particle Value—Lets you specify whether
the test passes par ticles on to the next event if the
age test succeeds or fails. Default=Is Greater Than
Te s t Va lu e
By default, Age Test returns True if the value tested
for exceeds the Test Value quantity, but you can
alternatively choose Is Less Than Test Value. For
example, if you use the Absolute Age test type and
setTestValue=60andVariation=0,andchooseIs
Less Than Te st Value, then particles will move to
the next event only until fr ame 60. After frame 60,
any remaining par ticles stay in the cur rent event
unless another test returns Tr ue.
Test Value—The sp e cific frame number, p article
age (in frames), or event duration (in fr ames) to
test for. Default=30.
This value cannot be animated.
Variation—The number of frames by which 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 etween -1.0 and 1.0, and then adds the
result to the Test Value setting. For example, if Test
Value=300 and Variation=10, then tested value for
each par ticle would be between 290 and 310.
Subframe Sampling—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 separate "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.