Flocking affects how particles behave and interact with each other, either within the group or with particles in other systems. Particles move with an awareness of each other. They can be attracted or repelled by one another. They can also move toward the same goals or targets.
Turn on Enable Tracking
to activate the Flocking simulation.
Attract defines the particle’s tendency to move towards the center of the group.
Separate controls the tendency of particles to push apart at very close proximity to each other, almost like two negative magnetic poles repelling.
Align controls the tendency of any particle to orient with nearby particles nearby, as a flock of birds or a school of fish will do. For more randomness to individual direction, as with insects, set this value at a low number.
Predator/Prey Behavior sets up the relationships between systems:
When set up as Prey, Evade
lets you control how much particles want to avoid a Predator.
If that system is set to Predator, Pursue
controls how hungry particles are.
On Predator/Prey Contact - This is available when a particle system is identified as predator. When a predator particle system comes into contact with particles from a prey system, there are five outcomes to choose from. These are:
Do Nothing: When individual predator particles come into contact (touch)with individual prey particles, nothing happens. The prey particles are still influenced by all the original properties set in the various sections/blocks.
Kill Prey: When individual predator particles come into contact (touch) individual prey particles, the prey particles will die (vanish). In other words, the particles' lifespan gets overwritten.
Blue predator particles are set to kill the white grid particles.
Kill Both: When individual predator particles come into contact (touch) individual prey particles, the predator and prey particles will both die (vanish).
Freeze Prey: When individual predator particles come into contact (touch) with individual prey particles, the prey particles lose all motion. All speed or environment influences no longer influence affected prey particles.
Convert Prey to Predator: When individual predator particles come into contact (touch) with individual prey particles, the prey particles change into whatever the predator particle is. For instance, if the predator particle is a purple cell sprite and the prey is a blue cell sprite, the blue cell (prey) will change to a purple cell (predator).
The blue predator particles are set to kill the white grid particles.
Team: This option is available when a particle system is identified with predator or prey behavior. You can assign a particle system to be part of one of four teams (A, B, C, or D). This is good to use when you want a predator system involved in a simulation with several other prey systems and you want the predator system only to attack specific prey systems and ignore others. By assigning a predator and prey system to the same team, the predator will not attack its own system's prey. It will only attack prey from different teams or prey not assigned to any team.
In the below example, the blue particles are from Team A and the red from Team B. The moving particles are predator systems and the static ones are prey. The blue predator particles only attack red prey particles and vice versa because of their team assignments. Without teams, the red and blue predator particles would attack all prey particles.
Maximum Speed
limits how fast each particle will travel.
Range of View
is the distance (in pixels) across your composite that the particles can "see."
Range of View Falloff
adds a feather to that Range of View distance to control how quickly particles snap to awareness.
Field of View
is your particles' angle of sight. For instance, you can simulate a predator that has eyes on the front of its head with a 180-degree field of view, chasing prey with eyes on the sides of their heads and a 270-degree field of view.
Target
Particles can also be driven to a Target
location/path:
Set a point for the
Target Position
(which can be animated).
Dial in the amount of
Target Attraction
particles have. At 0%, they are not drawn to the target at all, whereas at 100% that is all they want to get to.
Maximum Speed
controls how fast they can travel.
Range of View
sets the distance (in pixels) across your composite that particles can see. If the target is outside of this range, they won’t be attracted to it because they won't notice it.
Range of View Falloff
adds a feather to that Range of View distance to control how quickly particles snap to awareness.
These controls can be mixed and matched for a vast variety of uses. For example, here’s a grid set with Prey Evade turned up, meaning they will get out of the way when a Predator particle passes by them.
