Particles are essentially 2D images rendered in 3D space. They are primarily used for effects such as smoke, fire, water droplets, or leaves. A Particle System is made up of three separate Components: Particle Emitter, Particle Animator, and a Particle Renderer. You can use a Particle Emitter and Renderer together if you want static particles. The Particle Animator will move particles in different directions and change colors. You also have access to each individual particle in a particle system via scripting, so you can create your own unique behaviors that way if you choose.
This section describes the various components available in the legacy particle system.