The Throw behavior is the simplest way of setting an object in motion. Controls let you
adjust the speed and direction of a single force that’s exerted on the object at the first
frame of the behavior. After this initial force is applied, the object continues drifting in a
straight line at the same speed, for the duration of the Throw behavior.
A simple example of using the Throw behavior is to send a series of offscreen objects
moving across the screen. When used in conjunction with other behaviors such as
Grow/Shrink and Fade In/Fade Out, you can create sophisticated moving elements without
keyframing a single parameter.
The Throw behavior is also useful when you’re moving an object through a simulation.
For example, you might move the object past other objects that have Attractor or Repel
behaviors applied to them. Because the Throw behavior only applies a single force to
move the target object at the initial frame of the behavior, any other behaviors that
interact with the target object have potentially greater influence over its motion.
The Throw behavior does not apply a continuous force, nor can you create
changes in direction or speed, because Throw cannot be keyframed. To create keyframed
changes in direction or speed, use the Wind behavior. To create a more complex animation
path, use the Motion Path behavior.
Parameters in the Inspector
This parameter appears when Throw is applied to an object that
contains multiple objects, such as a group, particle emitter, or text. When this checkbox
is selected, each object within a parent object moves as an individual object. When this
checkbox is deselected, the entire layer or group moves as a whole.
This pop-up menu lets you choose how the behavior’s effect progresses over
its duration in the Timeline. There are two choices:
• Continuous Rate: Sets the speed of the object at a steady number of pixels per second,
specified in the Throw Velocity parameter.
Note: If the Canvas is displaying a nonsquare pixel image, the vertical rate is in pixels
per second, and the horizontal rate is the perceptual equivalent.
• Ramp to Final Value: Moves the object from its original position to the specified distance
(in pixels) in the Throw Distance parameter.
Throw Velocity/Throw Distance:
When the Increment pop-up menu is set to Continuous
Rate, the Throw Velocity parameter appears, which lets you set a continuous speed for
the object to move in X, Y, or Z space. When the Increment pop-up menu is set to Ramp
to Final Value, the Throw Distance parameter appears, which sets a total distance (in
pixels) for the object to travel in X, Y, and Z space over its duration. The slider is limited
to 100 pixels. Use the value field to enter values greater than 100.
The 2D HUD lets you specify the direction and speed of the Throw behavior by dragging
an arrow in a circular region. The direction of the arrow defines the direction of movement
in X and Y space, and the length of the arrow defines speed (velocity). A slider to the right
lets you adjust the scale of the HUD control, increasing or decreasing the effect the
direction/speed control has over the object.
Adjusts the scale of
the direction control,
and speed of throw
When you click the 3D button, additional 3D controls become available. The center arrow
now defines the direction the object is thrown in 3D space (X, Y, and Z axes). The Speed
slider (on the left side of the HUD) lets you increase or decrease the velocity of the thrown
Adjusts velocity of throw
Adjusts direction in X, Y,
and Z space
In the 2D and 3D Throw HUDs, press the Shift key while dragging the arrow to constrain
it to 45 degree angles. In the 2D HUD, press the Command key to change the arrow’s
direction without affecting its length.
Note: The maximum speed you can define with the HUD is not the maximum possible
speed. Higher values can be entered into the Throw Velocity/Throw Distance parameter
in the Behaviors Inspector.