Particle systems are useful for a variety of animation tasks. Primarily, they're employed when animating a large number of small objects using procedural methods; for instance, creating a snowstorm, a stream of water, or an explosion. 3ds Max provides two different types of particle systems: event-driven and non-event-driven. The event-driven particle system, Particle Flow, tests particle properties, and, based on the test results, sends them to different events. Each event assigns various attributes and behaviors to the particles while they're in the event. In the non-event-driven systems, particles typically exhibit consistent properties throughout the animation.
Having access to a wealth of particle systems in 3ds Max leads to the need to decide which system to use for a particular application. In general, for a simple animation, such as falling snow or a water fountain, setup is faster and easier with a non-event-driven particle system. With more complex animations, such as an explosion that generates different types of particles over time (for example: fragments, fire, and smoke), use Particle Flow for greatest flexibility and control.
Particle Flow is a versatile, powerful particle system for 3ds Max. It employs an event-driven model, using a special dialog called Particle View. In Particle View, you combine individual operators that describe particle properties such as shape, speed, direction, and rotation over a period of time into groups called events. Each operator provides a set of parameters, many of which you can animate to change particle behavior during the event. As the event transpires, Particle Flow continually evaluates each operator in the list and updates the particle system accordingly.
Non-event-driven particle systems provide relatively simple, straightforward methods for generating particle sub-objects over time for the purpose of simulating snow, rain, dust, and so on. You use particle systems primarily in animations. 3ds Max provides six built-in, non-event-driven particle systems: Spray, Snow, Super Spray, Blizzard, PArray, and PCloud.
