2009

Any object hierarchy can be displayed as bones.
Bones can scale, squash and stretch over time. See
Using Objects as Bones on
page 913.
Link Display
You can use Display Links and Link Replaces Object to display the links instead
of the object. These settings are found on the Link Display rollout on the
Display panel. This can be useful if you have a geometrically intensive
hierarchy to animate. The interactive viewport response is faster when the
geometry is hidden and displayed only at links.
Advantages of Animating Bones with IK
It is possible to animate a character's motion through forward kinematics,
rotating each limb into position from the shoulder to the fingers, and the hips
to the toes. But it's a lot quicker and more realistic to use inverse kinematics
to simulate the foot interacting with the ground. And it is a lot easier to control
when you need to make changes to the animation. Rather than having
keyframes on every bone in the chain, you have to make changes to only one
node, to change the animation of the entire chain.
On the other hand, it is common for animators to use IK for the legs and FK
for the torso and the arms. FK offers a bit more control for posing the upper
body. It is not necessary to use IK for every character animation task. Using
the HI IK solver allows you to jump back and forth easily between FK and IK.
3388 | Chapter 15 Animation