When you work with a biped, you can use inverse kinematics (IK) by moving the hands or feet in freeform animation. For example, you can position an arm by moving the hand.
A biped has three inverse kinematics parameters that you can vary during the limb's motion by setting them at each key of the arm and leg tracks. As the limb moves through each key:
- IK Blend Sets the motion interpolation to be a blend of forward and inverse kinematics. This will allow you to blend swinging motions with directed hand or foot motions. The default is 0.0, or full forward kinematics.
- Body or Object Determines the reference coordinate space of the IK path. This allows you to move the IK path with your character's body, or temporarily attach a hand or foot to follow another object or be attached to world space. The default is Body.
- Join to Previous IK Key Determines if the key should be part of the previous key (with the same reference position as the previous key).
These controls are in the IK section of the Key Info rollout.