Rubber-Banding Arms and Legs

Rubber Band mode provides a way to proportion the arm and leg links simultaneously. Rubber Band mode works with the Move transform rather than the Scale transform. When you move an arm or leg with Rubber Band mode turned on, both the link and its child are scaled in a single step.

Rubber-banding the upper arm rescales the upper and lower arm objects and moves the elbow link without affecting the position of the shoulder or the wrist. If you’ve spent a lot of time getting the fingers in the right place, you can reposition the elbow by rubber-banding, without affecting the hands.

Using Rubber Band to resize an arm without changing the hand position

Procedures

To rubber band an arm or leg link:

1. On the Motion panel Biped rollout, turn on (Figure Mode).
2. Select the arm or leg link you want to rubber band.
3. Click (Select And Move).
4. On the Biped rollout Modes group, turn on (Rubber Band Mode).
   Note: This button is unavailable if you are not in Figure mode, or if a part of the biped other than the upper or lower arm or leg, or the center of mass is selected.
   Note: The Modes group is hidden by default. To display it, click the expansion bar on the Biped rollout.
5. Move the selected arm or leg link.

   As you move the arm or leg link, the hands and feet are stationary as the knees or elbows are positioned.

To adjust the biped center of mass with Rubber Band:

1. On the Motion panel Biped rollout, turn on (Figure Mode).
2. Select the biped’s center-of-mass object (the diamond-shape object at the pelvis).
3. Click (Select And Move).
4. On the Biped rollout Modes group, turn on (Rubber Band Mode).

   This button is unavailable if you are not in Figure mode or if a part of the biped other than the upper or lower arm or leg or if the center of mass is selected.

5. Move the center of mass.

   While Rubber Band mode is active, the center of mass moves independently from the rest of the biped, which remains in the same position.

   Tip: Another way to adjust the biped’s balance is to change the value of Balance Factor. Balance Factor displays on the Key Info rollout when a Body Horizontal key is current. Balance Factor can be keyframed.