Specifying the frames you want to map (PB only)

A multiframe layer is any layer whose source varies over time, such as a movie or a composition. When you map new particles from a multiframe layer, use Time Offset to specify how you want to use the layer's frames. This provides even more flexibility for the range of source footage you can use in a single particle animation.

For example, use Absolute Time Offset to map an unchanging image onto a particle, or use Relative Time Offset to map an animating sequence of frames onto a particle. Both Relative and Absolute Time Offset can be randomized across particles.


A. Layer of a movie source that stores different, nonsequential objects in each frame B. Using Absolute Random Time Offset to create particles from that layer

Using Time Offset, you can choose a frame from which to start playing sequential frames from the source layer you're using to create particles. This way, you can achieve more realistic particle effects. For example, if you are using a source layer of a bird flapping its wings with a Relative Time Offset of 0 (zero), the flapping wings for all the instances of the bird will be 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 source layer, specify a Relative Random Time Offset when you set Layer Map options.

You can adjust the following Time Offset types for Layer Map:

Relative

Starts playing the source layer (the layer selected in the Use Layer menu of the Layer Map property) at a frame based on the Time Offset you specify, relative to the Playground layer's current time. When you use this option, the source layer frame, which displays as each particle, advances in step with the Playground layer's current time.

If you choose Relative and specify a Time Offset of 0, all particles shows the frame of the source layer that corresponds to the Playground layer's current time. However, if you choose Relative and specify a Time Offset of 0.1 (and your composition is set to 30 fps), each new particle starts displaying the source layer frame that is 0.1 seconds after the previous particle's frame, or every third frame. Therefore, as the Playground layer plays, the first particle shows the frame of the source layer that corresponds to the Playground layer's current time, the second particle shows the frame of the source layer that is 0.1 seconds later than the current time, the third particle shows the frame of the source layer that is 0.2 seconds later than the current time, and so on.

Note that regardless of the Time Offset you specify, the first particle always displays the frame of the source layer that corresponds to the Playground layer's current time.

Absolute

Displays a frame from the source layer based on the Time Offset you specify, regardless of the current time. Use this option 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 Playground 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 source layer earlier in time until the frame you want to show corresponds to the In point of the Playground layer. If you specify a Time Offset of 0.1, each new particle will display a frame that is 0.1 seconds after that of the previous particle (or every third frame of a 30-fps animation).

Relative Random

Starts playing the source layer from a frame chosen at random, within the range between the Playground layer's current time and the Random Time Max you specify (when you use a random Time Offset type, the Time Offset option changes to the Random Time Max option). For example, if you choose Relative Random and specify a Random Time Max of 1, each particle starts playing from a source layer frame chosen at random from between the current time and 1 second after the current time. If you choose Relative Random and specify a negative Random Time Max value, the Random Time Max will be before the current time, so that the range within which new particles start playing will advance as the current time advances, but will always be between the current time and one second earlier than the current time.

Absolute Random

Takes a frame at random from the source layer, using a time between 0 and the Random Time Max you specify. Use this option when you want each particle to represent a different single frame of a multiframe source layer. For example, if you choose Absolute Random and specify a Random Time Max of 1, each particle shows a source layer frame from a random time between 0 and 1 second into the source layer's duration.