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.
Interface
The user interface appears in the parameters panel, on the right side of the Particle View dialog.
- [age type drop-down list]
- The first interface element is a drop-down list that lets you choose the type of age to test. Default=Particle Age.
- Absolute Age Tests the current frame number in the animation.
- Particle Age Tests the current age of each particle in frames. This is the default test type.
- Event Age Tests the current duration of the current event in frames.
Test True If Particle Value group
Lets you specify whether the test passes particles on to the next event if the age test succeeds or fails. Default=Is Greater Than Test Value
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 set Test Value=60 and Variation=0, and choose Is Less Than Test Value, then particles will move to the next event only until frame 60. After 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 duration (in frames) 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 between -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 particle would be between 290 and 310.
- Subframe Sampling
- Turning this on helps avoid 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.
- Adjustable Age
- The Script and Data operators can modify the age of particles on the fly. However, for performance purposes the Age Test caches each particle's age when it first enters the event, and then uses the cached value for testing. Modifying the age after the particle enters the event can create test discrepancies. This option resolves this issue. If the event contains Script or Data operators that modify particle age or event age, turn Adjustable Age on.
Uniqueness group
The Uniqueness setting enables randomization of the test value variation.
- Seed
- Specifies a randomization value.
- New
- Calculates a new seed using a randomization formula.