2009

■ You apply a Noise controller to the X Rotation track of a window shutter
object to make it rattle, but the object intersects the building at the lower
end of its motion range. Apply a Limit controller to the track and set the
Lower Limit value to prevent the intersection.
■ Following from the previous example, say the wind tears the window
shutter from the building at frame 100. If the Noise controller is in a Float
List with a Bezier Float, you can weight the noise to 0 at frame 100, when
the shutter is torn from the building by the wind, at which point the
animator will key the animation. Limits are unnecessary after frame 100.
At frame 99, you'd use Set Lower Limit. Then, at frame 100, you'd edit the
Lower Limit value to set the limit to much lower, essentially removing the
limit. Finally, you would set keyframes to animate its movement past frame
100.
Limitations of the Limit Controller
It's important to be aware of the following limitations of Limit controllers:
■ Limit controllers do not limit IK joints. All IK solvers use their own limits,
and ignore Limit controllers. Interactive IK uses the current controllers,
but it also has its own limits, so using Limit controllers with interactive
IK will produce unpredictable results.
■ The Limit controller currently supports only Float controllers. Thus, the
Limit controller is currently available only under the name Float Limit.
■ Upper and lower limits values are expressed in the same units or coordinates
as those used by the limited controller. Thus, for example, Float limits on
an X Position track are in local coordinates, not in global coordinates.
Procedures
Example: To use the Limit controller:
1 Start with an animated object, and open Curve Editor.
In this example, the teapot position was animated on the X axis between
extents of about -45 to 40, and on the Y axis between extents of about
-80 and 54.
Limit Controller | 3183