![]() |
![]() |
Modeling > Modeling Characters >About inverse and forward kinematics
About inverse and forward kinematics
By creating limbs, you can use inverse kinematics (IK) and forward kinematics (FK) to animate characters.
Inverse kinematics allow you to create a simple bone structure, for instance, a leg (with the femur and shinbone), and it calculates the rotation values of both bones as you translate the shin around. What this means is that you can simply select the shin and drag it around and inverse kinematics will update the position and orientation of both bones for you.
With forward kinematics, rotation values of different limbs are keyed, so limbs are being animated in a more traditional sense, which allows a larger degree of control. In IK, the rotation of angles and shape of the limbs is being decided for you as you manipulate the last bone, whereas in FK, you decide the exact rotation of each limb yourself. It is therefore more labor-intensive, but you can still use the power of a bone structure to deform and animate surfaces.
It should also be noted that some types of bone structures, like the spine, bend in ways that IK does not really account for, so FK is sometimes the best way to go.
![]() |
![]() |