Aux System group> Subgroups

The Aux System is a particle system within the main particle system. Aux particles are emitted from the main particles system, and their behavior is great for creating effects like particle trails. Read our 'Emitting Particles from Particles' tutorial at the bottom of this page.

Version 1.5 Note: All of the Aux controls listed on this page were originally located in the Options Panel. They are now more easily accessible in Aux System subgroups.

Control from Main Particles group

The Control From Main Particles subgroup lets you modify how and when the Aux particles are emitted by the Aux System. Useful for getting more variation in the Aux particle behavior, which contributes to a more natural effect. There are three controls in this group.

Inherit Velocity (Options Panel in v1.5)

The Inherit Velocity control lets you add motion to the Aux particles. Inherit Velocity limits the creation of Aux particles based on the lifetime of the main particle. High values make the Aux particles move faster because they start out with, or 'inherit', more velocity. The main particle velocity is set in Emitter group> Velocity.

Start Emit, Stop Emit [% of Life] (Options Panel in v1.5)

The Start and Stop Percentage controls define when the Aux particles appear in the life of the main particles. The Start and Stop values are a percentage of the Particle> Life [sec] value. For example, if Start and Stop are set to 20 and 80, then the Aux particles will appear starting at 20% of the main particle Life [sec] value and will stop appearing at 80% of the same value. A value of 0 and 100 respectively will emit Aux particles from the beginning to the end of the main particle's life.

Physics (Air mode only)

The Physics Air subgroup gives the Aux particles separate settings for three controls in the Physics> Air group. This lets the Aux particles take on different physics-based behavior than the main particles, which can make your animation more interesting. There are three controls in this group.

Air Resistance (Options Panel in v1.5)

Air Resistance will modify the value set in Physics> Air> Air Resistance. A value of 0 adds no air resistance. A value of 255 causes full air resistance modification to just the aux particles.

Wind Affect [%] (Options Panel in v1.5)

Wind Affect is a multiplier that will increase the Physics> Air> Wind motion in X, Y, and Z space for the Aux particles. Wind Affect is measured in a percentage. With values less than 100, Wind Affect decreases the Wind motion speed. With values greater than 100, Wind Affect multiplies and increases the Wind motion speed.

For example, a Wind Affecct value of 80 causes the Aux particles to move at .8 times the Wind values in the Physics> Air section. A value of 275 will multiple the Wind values by 2.75 times the original speed.

Turbulence (Options Panel in v1.5)

Turbulence Position is the same setting as Affect Position value in the Physics> Air> Turbulence Field group. However, this Turbulence control only changes the Aux particles offset by the Turbulence Field. It does not affect the displacement of the main particles.

Randomness group

The Randomness subgroup applies a randomness value to related parameters in the main Aux System group. Useful for getting more natural variation in the overall particle behavior. There are three controls in this group.

Life (Options Panel in v1.5)

Life sets a randomness factor to how long the Aux particles live. Affects the Life [sec] value in Aux System group.

Size (Options Panel in v1.5)

Size sets a randomness factor to the size of the Aux particles. Affects the Size value in Aux System group.

Opacity (Options Panel in v1.5)

Opacity sets a randomness factor to the opacity of the Aux particles. Affects the Opacity value in Aux System group.

Tutorial: Emitting Particles from Particles

Let's emit some particles with the Aux System. Start with a new comp (Ctrl/Cmd-N). Make it 640*480 at 30 fps. 5 seconds long. Create a comp-sized Solid (Ctrl/Cmd-Y), choose Make Comp Size, and click OK. Apply Effect> Trapcode> Particular to the Solid.
When emitting particles from particles, you can easily generate an overwhelming amount of particles. Let's start by decreasing the emission of the main particle system. Set Emitter> Particles/sec to 20. Try a RAM preview. Not too exciting.

Basic Aux particles.

We will get the excitement going by activating the Aux System. Set Aux System> Emit to Continuously. Set Type to Same as Main. To make the Aux Particles stronger, set Aux System> Opacity to 100.

Hit RAM preview again. Now we have particles generated from the particles.

Particle Trace Effect. To get a long trace for each particle, set Aux System> Life to 5. This way the Aux Particles lives long enough to produce a long trail. To get a denser trace, set Aux System> Particles/sec to 20. Try RAM preview: |  |

Organic Lines Effect. So far, the Aux Particles have just been standing still. Let's see what happens if we put some motion to them. Let's add some gravity by setting Gravity to 100, and then click OK. Try RAM preview: Notice that the Aux System has its own Gravity control. To change gravity for the main particles, use Physics> Gravity instead. |  |

Particle Trail Effect.

Now let's roughen up the animation a bit and make it look more like each particle is emitting a heavy trail. We'll do this by giving the Aux Particles some initial, random, velocity. Set Aux System>Velocity to 10. Hit RAM preview: