Activity 8: Spring Tool


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.
  • The number of frames between poses in the pose layer.
  • The total number of frames in the pose layer.
  • The number of frames between the final pose and the last frame of the pose later.

Additional resources


Go to: and complete the following sections:

  1. Spring tool basics,
    • Save as:  firstname_activity 9_spring.fla
    • Export as: firstname_activity 9_spring.swf
  2. Advanced Spring techniques
    • Save as: firstname_activity 8_advspring.fla
    • Export as: firstname_activity 8_advspring.swf
  3. Now upload your two swf files here: