The basic function of a test in Particle Flow is to determine whether particles satisfy one or more conditions, and if so, make them available for sending to another event.

When a particle passes a test, it is said to “test True.” To send eligible particles to another event, you must wire the test to that event. Particles that don't pass the test (“test False”) remain in the event and are repeatedly subjected to its operators and tests. Or, if the test isn't wired to another event, all particles remain in the event. You can use several tests in an event; the first test checks all particles in the event, and each test after the first checks only particles that remain in the event.

One test, Spawn, doesn't actually perform a test, but simply creates new particles from existing ones, and sets the new particles' test result to True so they're automatically eligible for redirection to another event. And the Send Out test simply sends all particles to the next event by default.

Some tests can also serve as operators, in that they contain parameters that modify particle behavior. If you don't wire a test to another event, it functions only as an operator; the test aspect doesn't affect particle flow.

TipAlways place a test at the end of its event, unless you have specific reasons for placing it elsewhere. That way, all preceding actions can take effect during each integration step before the test is evaluated.

All the tests are grouped together in the Particle View depot, and are listed in alphabetical order. The icon for all tests is a yellow diamond, usually containing a simplified diagram of an electrical switch.

The Particle Flow tests in the Particle View depot

See Also