A Particle System consists of a predefined set of modules that can be enabled and disabled. These modules describe the behavior of particles in an individual particle system.
Initially only a few modules are enabled. Addding or removing modules changes the behavior of the particle system. You can add new modules by pressing the (+) sign in the top-right corner of the Particle System Inspector. This pops up a selection menu, where you can choose the module you want to enable.
An alternative way to work with modules is to select "Show All Modules", at which point all of the modules will show up in the inspector.
Then you can enable / disable modules directly from the inspector by clicking the checkbox to the left.
For details on individual modules and their properties, see Particle System Modules
Page last updated: 2012-10-25