ADOBE AFTER EFFECTS 7.0
User Guide
504
Some Persistent Property Mapper and Ephemeral Property Mapper options can make explosions more realistic. For
example,changeOpacitytomaketheresultingparticlesfadeout,orchangetheRed,Green,andBluecolorchannels
to make resulting particles change color as they appear to cool. (See “About Property Mappers and Particle Playground
(Pro only)” on page 508.)
Layer Exploder and Particle Exploder controls (Pro only)
Explode Layer (Layer Exploder only) Specifies the layer you want to explode. To make the video disappear the
moment the particles appear, either turn off the video for the layer or trim the layer’s Out point.
Radius Of New Particles Specifies the radius of the particles resulting from the explosion. This value must be smaller
than the radius of the original layer or particle.
Velocity Dispersion Specifies, in pixels per second, the maximum speed of the range within which Particle
Playground varies the velocity of the resulting particles. High values create a more dispersed or cloudlike explosion.
Low values keep the new particles closer together and can make the exploded particles resemble a halo or shock
wave.
Affects Specifies which particles are affected by the Layer Exploder and Particle Exploder. (See “Affects controls for
Particle Playground (Pro only)” on page 508.)
Replacing default particles with layers using Layer Map (Pro only)
By default, the Cannon, Grid, Layer Exploder, and Particle Exploder create dot particles. To replace the dots with a
layer in the composition, use the Layer Map. For example, if you use a movie of a single bird flapping wings as a
particle source layer, After Effects replaces all dots with an instance of the bird movie, creating a flock of birds. A
particle source layer can be a still image, a solid, or a nested After Effects composition.
A multiframe layer isanylayerwithasourcethatvariesovertime,suchasamovieoracomposition.Whenyoumap
new particles to a multiframe layer, use the Time Offset Type control to specify how you want to use the layer’s
frames. For example, use Absolute to map an unchanging image onto a particle, or use Relative to map an animating
sequence of frames onto a particle. You can randomize both Absolute and Relative across particles.
Note: WhenyouchoosealayerforLayerMap,ParticlePlaygroundignoresanypropertyorkeyframechangesthatyou
made to that layer within that composition. Instead, it uses the layer in its original state. To keep transformations, effects,
masks, rasterization options, or keyframe changes for a layer when you use it as a particle source, precompose the layer.
Layer Map controls for Particle Playground (Pro only)
Use Layer Specifies the layer you want to use as the particles.
Time Offset Type Specifies how you want to use a multiframe layer’s frames. For example, if you are using a layer of
a bird flapping its wings and you choose Relative for Time Offset Type with a Time Offset of 0, the flapping wings
for all the instances of the bird are synchronized. While this might be realistic for a marching band, it is not realistic
for a flock of birds. To make each bird start flapping its wings from a different frame in the layer, use Relative
Random.
• Relative Starts playing the layer at a frame based on the Time Offset you specify, relative to the effect layer’s
current time; then advances in step with the Particle Playground layer’s current time. If you specify a Time Offset of
0, all particles show the frame that corresponds to the effect layer's current time. If you choose a Time Offset of 0.1
(and your composition is set to 30 fps), each new particle displays the frame that is 0.1 seconds after the previous
particle’s frame. Regardless of the Time Offset you specify, the first particle always displays the frame of the source
layer that corresponds to the effect layer’s current time.
• Absolute Displays a frame from the layer based on the Time Offset you specify, regardless of the current time.
ChooseAbsolutewhenyouwantaparticletoshowthesameframeofamultiframesourcelayerforitsentirelifespan,
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