Spin
Apply the Spin behavior to animate the rotation of an object, spinning it around a single
axis. Using the Custom axis controls, the rotation does not have to occur on a principle
axis (X, Y, or Z). If you trim the end of the Spin behavior to be shorter than the duration
of the object to which it is applied, it remains at the angle of the last frame of the behavior,
as long as there are no other behaviors or keyframes affecting that object’s Rotation
parameter.
Uses for Spin are fairly obvious, but another way to use the Spin behavior is with objects
that have an off-center anchor point. Because objects rotate around the anchor point, if
you change an object’s anchor point before you apply a Spin behavior to it, you can
change the look of the motion you create. For more information on changing an object’s
anchor point, see
Using the Anchor Point Tool
.
Note: Although the Spin behavior appears in the Basic Motion category, Spin is treated
as a Simulation behavior in Motion’s order of operations. For more information, see
Behavior Order of Operations
.
Parameters in the Inspector
Affect Subobjects:
This parameter appears when Spin is applied to an object that contains
multiple objects, such as a group, particle emitter, or text. When this checkbox is selected,
each object in the layer or group rotates as an individual object. When this checkbox is
deselected, the entire layer or group spins.
Increment:
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: Uses the Spin Rate parameter to spin the object by a steady number
of degrees per second.
• Ramp to Final Value: Spins the object for the number of degrees specified in the Spin
To parameter over the behavior’s duration in the Timeline.
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Spin Rate/Spin To:
A dial controlling the speed at which the object spins. When Increment
is set to Continuous Rate, the Spin Rate defines a continuous rate of spin in degrees per
second. When Increment is set to Ramp to Final Value, Spin To defines a number of
degrees to spin over that object’s duration. Negative values result in clockwise motion,
while positive values result in counterclockwise motion.
Axis:
A pop-up menu that allows you to choose whether the object spins about the X,
Y, or Z axis. You can also choose Custom, which yields additional Longitude and Latitude
parameters. The following illustration shows the Spin behavior’s HUD control set to the
Z axis.
When Axis is set to Custom, additional Longitude and Latitude parameters become
available. These parameters allow the object to spin at an angle (not locked to the X, Y,
or Z axes). If you’re working on an object in a 3D group, you can also drag the axis control
in any direction to simultaneously modify the longitude and latitude of spin, as seen in
the following illustration.
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The following image shows how longitude and latitude relate to the Spin HUD control.
Y
X
Z
Latitude
Longitude
• Latitude/Longitude: Available when Axis is set to Custom (or by dragging the center
control of the Spin HUD), these parameters allow you to specify the axis of rotation.
HUD Controls
The Spin behavior’s HUD controls include an outer ring and an inner control. Drag along
the edge of the outer ring to manipulate an arrow that indicates the direction and speed
the object spins. Adjust the length of the arrow to change the speed at which the spinning
occurs—drag around multiple times to increase the rate of the spin.
The inner arrow controls the axis about which the object or group spins. When you drag
the inner controls, a globe control becomes available that allows you to adjust the object’s
spin in degrees longitude and latitude.
Note: You can spin the arrow around the ring multiple times to rotate the object more
quickly.
Controls direction
and speed of spin
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