Apple Motion 2 User Manual

Page 378

378

Chapter 5

Using Behaviors

Influence: A slider that defines the radius of the circle of influence, in pixels. Objects
that fall within the area of influence move toward the object of attraction. Objects that
are outside of the area of influence remain where they are.

Drag: A slider that can be used to reduce the distance attracted objects overshoot the
object of attraction. Lower Drag values result in the object overshooting the object of
attraction, moving past and then careening back around toward the target object
again and again. Higher Drag values result in the object coming to rest sooner.

Related behaviors
“

Edge Collision

This is a good behavior to use if you’re setting up complex motion simulations and you
don’t want your objects exiting the Canvas. Objects with the Edge Collision behavior
applied either come to a stop or bounce off after colliding with the edge of the Canvas
frame. For example, if you applied the Throw behavior to an object and set the velocity
to send the object toward the edge of the frame, then applied Edge Collision, the
object would hit the edge of the frame, then bounce off according to the Bounce
Strength parameter.

The angle in which the object bounces depends on the angle with which it hits the
edge of the frame, while the speed it travels after bouncing is set by the Bounce
Strength parameter.

Important:

With most objects, the Edge Collision behavior uses the bounding box to

determine how the object collides with the edge of the Canvas. If you’re using this
behavior with an object that has an alpha channel that’s smaller than its bounding box,
adjust the Crop parameter in the object’s Properties tab to fit the bounding box as
closely as possible to the edge of the image. With particles, text, and layers, only the
object’s center is used.

Animation path of a thrown object
affected by the Edge Collision behavior

Affects

Parameters affected

Object

Position

01112.book Page 378 Sunday, March 13, 2005 10:36 PM