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Falloff Type: A pop-up menu that determines whether the distance defined by the
Influence parameter falls off linearly or exponentially.
• Linear: Repulsion between objects falls off in proportion to the object’s distance.
• Exponential: The closer an object is within the area of influence, the more strongly it
is repelled, and the faster it moves away from the object doing the repelling.
Falloff Rate: This value determines how quickly the force of repulsion between objects
affected by this behavior falls off. A low Falloff Rate value results in objects quickly getting
up to speed as they move away from the object of repulsion. A high Falloff Rate causes
objects to accelerate much more slowly. When set to Exponential, the attraction falls off
more quickly than when set to Linear.
Influence: A slider that defines the radius of the circle of influence in pixels. Objects that
fall within the area of influence move away from the object of repulsion. Objects outside
the area of influence remain in place.
Drag: A slider that can be used to reduce the distance the object or objects travel away
from the repelling object.
Include X, Y, and Z: Buttons that allow you to specify the space in which the object
moves away from the selected object. For example, when X and Y are enabled, the object
moves in the XY plane; when Y and Z are enabled, the object moves in the YZ plane.
HUD Controls
The HUD has an image well you can use to assign an object to move away from, as well
as controls for Strength, Falloff Type, Falloff Rate, Influence, axis assignment, and Drag.
When applied to an object that contains multiple objects (such as a group, particles, text,
or the replicator), the Affect Subobjects checkbox also appears in the HUD.
Related Behaviors
• Repel
Rotational Drag
This behavior is similar to the Drag behavior, except that it affects Rotation instead of
position. Rotational Drag simulates friction affecting objects that are spinning due to
keyframed or behavior-driven changes to the Rotation parameter. By setting higher Drag
values, you can slow rotational changes to an eventual stop.
Parameters in the Inspector
Affect Subobjects: This parameter appears when this behavior is applied to an object
that contains multiple objects, such as a group, a particle emitter, a replicator, or a text
layer. When this checkbox is selected, all objects in the parent object are affected
individually. When this checkbox is deselected, all objects in the parent object are affected
by the behavior together.
Amount: A slider that can be used to slow down an object’s rotation over time, causing
it to eventually come to a stop. Higher Amount values result in the rotation ending sooner.
472 Chapter 9 Using Behaviors