Step 10: Setting & Memorizing Favored IK Angles

Poser’s inverse kinematics works based on the current rotations of a body part. Proper IK angles must be preset in the figure in order for IK to work predictably. The original joint rotation values help the IK logic know which way to bend some of the joints and will affect how the IK works as the figure moves. Setting and memorizing favored IK angles is therefore important.

Before memorizing the default positions for all of the body parts, you should bend the parts used in IK chains so that they favor their natural bending directions. For example, a standing person’s thighs bend slightly forward and out from vertical, and her or his shins bend slightly back and in.

These positions can be tested by lowering the hip joint in the Y (up/down) direction while IK is turned on for the legs. While doing this, the knees should bend smoothly, and not buckle or swing widely to either side.

Then, to test the arms, enable IK on the arms and move the chest side to side (X trans). The arms and shoulders should bend naturally. If they do not, add small amounts of rotation into the joint to correct the unnatural bending.

With IK off, return the hip to zero and the chest to zero. Preserve the rotations on the limbs. Make sure that they are symmetric from one side to the other. Then memorize figure to store the rotations.

To set favored IK angles:

1. Disable the affected IK chain(s).
2. Position each body part in the chain by slightly bending it in the direction it would bend under IK by a few degrees.
3. Save the angles by memorizing the body parts or the entire figure by selecting Edit > Memorize > Object or Edit > Memorize > Figure, respectively.
4. Enable the affected IK chain(s).

Please refer to Inverse Kinematics (IK) for more information about Poser’s Inverse Kinematics features.