Adobe After Effects - Manual (Page 570)

Explode Layer
Radius Of New Particles
Velocity Dispersion
Affects
Note:
Use Layer
Time Offset Type
source of the layer is transparent.
To change the position of the exploding layer, precompose the layer with its new position (use the Move All Attributes Into The New
Composition option), and then use the precomposed layer as the exploding layer.
When you explode particles, the new particles inherit the position, velocity, opacity, scale, and rotation of the original particles.
After layers or particles explode, Gravity, Repel, Wall, and Property Mapper controls influence the movement of particles.
Some Persistent Property Mapper and Ephemeral Property Mapper options can make explosions more realistic. For example, change Opacity
to make the resulting particles fade out, or change the Red, Green, and Blue color channels to make resulting particles change color as they
appear to cool.
(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 Out point of the layer.
Specifies the radius of the particles resulting from the explosion. This value must be smaller than the radius of the
original layer or particle.
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 shockwave.
Specifies which particles the Layer Exploder and Particle Exploder affect.
Layer Map controls
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 its 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 is any layer with a source that varies over time, such as a movie or a composition. When you map new particles to a multiframe
layer, use the Time Offset Type control to specify how you want to use the frames of the layer. 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.
When you choose a layer for Layer Map, Particle Playground ignores any changes that you made to that layer within that composition.
Instead, it uses the layer in its original state. To keep transformations, effects, masks, rasterization options, expressions, or keyframe changes for
a layer when you use it as a particle source, precompose the layer.
Specifies the layer you want to use as the particles.
Specifies how you want to use the frames of a multiframe layer. 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 may 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 current time of the effect layer; then advances in step with
the current time of the Particle Playground layer. If you specify a Time Offset of 0, all particles show the frame that corresponds to the current time
of the effect layer. 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 current time of the effect layer.
Absolute
Displays a frame from the layer based on the Time Offset you specify, regardless of the current time. Choose Absolute when you want a particle to
show the same frame of a multiframe source layer for its entire lifespan, instead of cycling through different frames as the effect layer advances in
time. For example, if you choose Absolute and specify a Time Offset of 0, every particle shows the first frame of the source layer for its entire
lifespan. If you want to show a frame other than the first frame, move the layer earlier in time until the frame you want to show corresponds to the
In point of the Particle Playground layer. If you specify a Time Offset of 0.1, for example, each new particle displays a frame that is 0.1 second
after the frame of the previous particle (or every third frame of a 30-fps animation).
Relative Random
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