ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with inverse kinematics
The following pairs of properties enforce these limits. The pairs consist of a Boolean value that indicates whether the
movement is limited and an integer that specifies the limit:
By default, all the Boolean values are set to false, so movement is not limited unless you explicitly set a Boolean value
to true. To enforce a limit, set the appropriate property to true and then specify a value for the corresponding integer
property. If you set the limit to a value without setting its corresponding Boolean property, the limit is ignored. In this
case, the IK engine continues to move the object until another limit or the target position of the IKMover is reached.
In the following example, the maximum distance of the armature movement is set to 0.1 pixels per iteration. The
maximum number of iterations for every movement is set to ten.
ik.limitByDistance = true;
ik.distanceLimit = 0.1;
ik.limitByIteration = true;
ik.iterationLimit = 10;
Moving an IK Armature
Flash Player 10 and later, Adobe AIR 1.5 and later, requires Flash CS4 or later
The IKMover moves the axle inside the event listener for the wheel. On each enterFrame event of the wheel, a new
target position for the armature is calculated. Using its moveTo() method, the IKMover moves the tail joint to its
target position or as far as it can within the constraints set by its limitByDistance, limitByIteration, and
limitByTime properties.
Wheel.addEventListener(Event.ENTER_FRAME, frameFunc);
function frameFunc(event:Event)
{
if (Wheel != null)
{
var mat:Matrix = Wheel.transform.matrix;
var pt = new Point(90,0);
pt = mat.transformPoint(pt);
}
Boolean property Integer property Limit set
limitByDistance:Boolean distanceLimit:int Sets the maximum distance in pixels that the IK engine moves for each
iteration.
limitByIteration:Boolean iterationLimit:int Sets the maximum number of iterations the IK engine performs for each
movement.
limitByTime:Boolean timeLimit:int Sets the maximum time in milliseconds allotted to the IK engine to
perform the movement.
}
ik.moveTo(pt);
Last updated 6/6/2012
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