Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 502

Specifies the radius of the particles resulting from the explosion. This value must be smaller
Radius Of New Particles
than the radius of the original layer or particle.
Specifies, in pixels per second, the maximum speed of the range within which Particle
Velocity Dispersion
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 are affected by the Layer Exploder and Particle Exploder.
Affects
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 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: 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, raster-
ization 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.
Use Layer
Specifies how you want to use a multiframe layer's frames. For example, if you are using a layer of
Time Offset Type
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.
•
Starts playing the layer at a frame based on the Time Offset you specify, relative to the effect layer's
Relative
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.
• Displays a frame from the layer based on the Time Offset you specify, regardless of the current time.
Absolute
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 that of the previous particle (or every third frame of a 30-fps
animation).
•
Starts playing the layer from a frame chosen at random, within the range between the effect
Relative Random
layer's current time and the Random Time Max you specify. For example, if you choose Relative Random and specify
a Random Time Max of 1, each particle starts playing from a layer frame chosen at random from between the current
time and 1 second after the current time. If, for another example, you specify a negative Random Time Max value of
- 1, the Random Time Max is before the current time, so that the range within which new particles start playing
AFTER EFFECTS CS3 496
User Guide