decorative banner

Influencing individual particles over their lifespan (PB only)


    To have full control over particle movement and appearance, you must balance the properties you assign to particles at particle birth (Cannon, Grid, Layer Exploder, and Particle Exploder) with the properties you assign to the particle's lifespan (Gravity, Repel, Wall, and Property Mapper). For example, if you want to use the Cannon to shoot sparks that fade over time, it may seem that you need only animate the Cannon's Color option. However, using this method, you change only the color of each new particle as it's created. To control the color for the lifespan of particles, you must create a layer map and use the Property Mapper to alter the particles' color channels.

    The following list covers common particle behavior. For more information on these items, see About Property Mappers (PB only).

    Speed

    At particle creation, particle velocity is set by the Cannon and the exploders; Grid particles have no initial speed. After particle creation, use the Force option in the Gravity and Repel properties. You can also influence the speed of individual particles by using a layer map to set values for the Speed, Kinetic Friction, Force, and Mass properties in the Property Mappers.

    Direction

    At particle creation, the Cannon includes particle direction, the Layer Exploder and Particle Exploder send new particles in all directions, and Grid particles have no initial direction. After particle creation, direction can be influenced by the Direction option in the Gravity property, or by using a mask with the Wall property. You can also influence the direction of individual particles by using a layer map to set values for the Gradient Force, X Speed, and Y Speed properties in the Property Mappers.

    Area

    Use a Wall mask to contain particles to a different area or to remove all barriers. You can also restrict particles to an area by using a layer map to set values for the Gradient Force property in the Property Mappers.

    Appearance

    At particle creation, the Cannon, Grid, Layer Exploder, and Particle Exploder operators set particle size unless you replace the default dots with a layer map. The Cannon and Grid set the initial color, while the Layer Exploder and Particle Exploder take color from the exploded dot, layer, or character. The Options dialog box affects the initial appearance of text. After particle creation, you can use the Property Mappers to set values for the Red, Green, Blue, Scale, Opacity, and Font Size properties.

    Rotation

    At particle creation, the Cannon and Grid set no rotation; the Particle Exploder takes rotation from the exploded dot, layer, or character. Use Auto-Orient Rotation to make particles rotate automatically along their respective trajectories; for instance, a particle can point up as it climbs an arc, and point down as it descends. Rotation isn't easily visible for a dot particle. It is easier to observe only when you replace the dot particle with text characters or a layer. After particle creation, use a layer map to set values for the Angle, Angular Velocity, and Torque properties in the Property Mappers.

    Note: The appearance and rotation of a layer map particle changes in relation to the mapped layer's original appearance and rotation. For instance, if you replace the default dot particles with a movie of a spinning wheel, the spinning-wheel particles appear to spin when no particle rotation is applied.

To rotate particles automatically along their trajectories:

  1. In the Effect Controls window under Particle Playground, click Options.
  2. Select Auto-Orient Rotation to turn it on, and click OK.