Mesh objects can have multiple particle systems. To add a new particle system to an object go to the Particle buttons in the Object [F7] menu and click Add New in the Particle System tab, or select an existing particle settings from the dropdown menu.

To add more particle systems to an object advance the active particle system (1 Part 1) selector to an empty slot by clicking it near its right edge. As with material indices, the number on the left of Part indicates the active particle system, while the number on the right indicates the number or particle systems available for the object.

For each particle system there is a corresponding modifier in the modifier stack. The particles are emitted from the mesh at the position of the particle system modifier in the stack.

• Datablock selector (PA:): here you can select particle settings, name them or delete particle systems.
  
• i Part j: selector for the active particle system.
• Type: menu for selecting the type of particles, among the three types available: Emitter, Reactor and Hair.
• Enable for rendering and interactive display: the buttons do the same thing as the corresponding buttons in the particle system modifier.

Emitter, reactor, hair and fluid particle system types are available. These can be enabled simply by selecting the type from a menu, with the exception of fluid particles. These are created indirectly through the fluid simulation system.

These parameters defines how the particles are emitted, giving precise control over their distribution.

• Random: the emitter element indices are gone through in a random order instead of linearly
• Emitter element: Verts, Faces, Volume states that particles are emitted respectively by vertices, faces, enclosed volume of the mesh emitter
• Even: particle distribution is made even based on surface area of the elements
• Distribution:
  • Jittered: particles are placed at jittered intervals on the emitter elements
    • Amount: amount of jitter applied to the sampling
    • P/F: number of emissions per face (0 == automatic).
  • Random: particles are placed randomly in the emitter elements
  • Grid: particles are set in a 3d grid and particles near/in the elements are kept
    • Invert: toggles what is considered to be the emitter

A few settings differ from the standard Emitter particles system type. Here are the differences:

• Sta/End: particles are only emitted when the chosen event happens (see React on, below). But with this option, you can force all remaining particles to be emitted within the Sta through End frames (the proper settings are displayed when this option is active).
• React on: which event of the target particles triggers emission: Death (target particle dies), Collision (target particle collides), Near (target particle in the vicinity of the Reactor)
• Multi React: allow reacting multiple times (alive particles react too and not just unborn particles)
• Shape: how reaction strength varies with distance from target particle. The closest, the stronger the reaction.

These parameters are mostly the same as the Emitter particles system type, to one exception:

• Emitter element: Particles is another possible option for Reactor particles systems, meaning that particles are emitted by other particles, when reacted on.

These parameters are only useful for Reactor systems, and are meant to define the particle system to which the Reactor system should react.

• OB: defines the object that has the target particle system, whose particles are evaluated in search for events to react to. If the field is blank, the current object is used.
• sys: selects which particle system is the target. Should appear red when no valid target is specified. This is always the case when the current particles system is the first particles system of the current object (OB: field empty)

• React on - Death: Particles are emitted when the target particles die. Two example usages:
  • Fireworks: Target particles are emitted upwards with normal gravity. Reactor particles are set to emit from particles with random initial velocity and similar gravity.
  • Minefield: Reactor particles emitted from a large volume with reactor initial velocity. Target particles that die inside the volume cause "explosions" when they die.

• React on - Collision: Particles are emitted when target particles collide with something. Example usage:
  • Raindrops: Reactor particles are on the ground plane with normal and reactor velocity. Target particles fall from above and collide with the ground plane.

• React on - Near: Particles are emitted when target particles are near them. Example usages:
  • Trails: Reactor particles set to emit from particles with random initial velocity. Now the reactor particles are always "near" the target particles so they emit constantly leaving a trail for the target particles.
  • Sand dunes: Reactor particles are emitted from the ground mesh with negative reactor velocity. When target particles fly over the ground they make reactor particles rise from the ground.

• Amount: the total amount of hairs to create.
• Segments: the number of segments the hair consists of, the key points of the curve that defines the hair. The default of 5 is good for fur, more segments can be used for longer hair.

These parameters are mostly the same as the Emitter particles system type.