Particle System

Particle systems are objects that generate non-editable sub-objects called particles, for the purpose of simulating snow, rain, dust, and so on.

The particle system object generates the particles over time. You use particle systems primarily in animations.

3ds max provides several built-in particle systems: Spray and Snow. You may have installed other plug-in particle systems.

The Deflector, Gravity, and Wind space warps are for use with particle systems. (Gravity and Wind also work with Dynamics.)