Adobe Flash Professional CC 2014 v.13.0 - Manual (Page 56)

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You set these properties in the Property inspector when one or more bones are selected.
To enable a selected bone to move along the x- or y- axis and change the length of its parent bone, select Enable in the Joint: X Translation
or Joint: Y Translation section of the Property inspector.
A two-headed arrow appears perpendicular to the bone on the joint to indicate that x-axis motion is enabled. A two-headed arrow appears
parallel to the bone on the joint to indicate that y-axis motion is enabled. Enabling both x and y translation for a bone simplifyies the task of
positioning the bone when rotation is disabled for the bone.
To limit the amount of motion enabled along the x- or y-axis, select Constrain in the Joint: X Translation or Joint: Y Translation section of the
Property inspector and enter a value for the minimum and maximum distance the bone can move.
To disable rotation of the selected bone around the joint, deselect the Enable checkbox in the Joint: Rotation section of the Property
inspector.
This checkbox is selected by default.
To constrain rotation of a bone, enter minimum and maximum degrees of rotation in the Joint: Rotation section of the Property inspector.
The degrees of rotation are relative to the parent bone. An arc appears on top of the bone joint indicating the degrees of freedom of rotation.
To make a selected bone stationary relative to its parent bone, disable rotation and x- and y-axis translation.
The bone becomes rigid and follows the motion of its parent.
To limit the speed of motion of a selected bone, enter a value in the Joint Speed field in the Property inspector.
Joint speed gives the bone the effect of weight. The maximum value of 100% is equivalent to unlimited speed.
Constraining bone movement with pinning (CS5.5 only)
You can prevent specific bones from moving by pinning them to the Stage. The pinned bones are fixed in place while the other bones attached to
them continue to move freely. An example of this in use would be a human figure with the bones of the feet pinned so that they cannot move
above of below the floor the figure is standing on.
To pin one or more bones to the Stage:
1. Select the bone(s) on the Stage by clicking them.
2. Do one of the following:
Place the mouse cursor over a bone joint until the Pin cursor appears. Then click the joint.
In the Location section of the Property inspector, select the Pin checkbox.
The selected bone can no longer move in any direction.
Videos and tutorials
Video: Flash Professional CS5.5 - Pinning Support for IK (2:35, Adobe TV)
Video: Spring for Bones (Length: 4:29, Includes: Add bones, contrain joint motion, add poses, animate with spring properties. AdobeTV.com)
TechNote: Unable to set an IK motion constraint on the last bone in a joint
Add Springiness to bones
Two bone properties can be used to add springiness to IK bones. The Strength and Damping properties of bones give real physical movement to
IK Bones by integrating dynamic physics into the Bones IK system. These properties allow easier creation of physics-enhanced animation. The
Strength and Damping properties give bone animation life-like movement that is highly configurable. It is best to set these properties before adding
poses to a pose layer.
Strength The stiffness of the spring. Higher values create a stiffer spring effect.
Damping The rate of decay of the spring effect. Higher values cause the springiness to diminish more quickly. A value of 0 causes the springiness
to remain at its full strength throughout the frames of the pose layer.
To enable springiness, select one or more bones and set the Strength and Damping values in the Spring section of the Property inspector. The
higher the Strength, the more rigid the spring becomes. Damping determines the rate of decay of the spring effect, so the higher the value, the
faster the animation ends.
To turn off the Strength and Damping properties, select the pose layer in the Timeline and deselect the Enable checkbox in the Spring section of
the Property inspector. This allows you to see on Stage the poses you have defined in the pose layer without the effect of the Spring properties.
The following factors affect the final look of your bones animation when working with the Spring properties. Experiment with adjusting each of
these to acheive the final look you want.
The Strength property value.
The Damping property value.
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