8

IK Solvers 425
Any object hierarchy can be displayed as bones.
Bones can scale, squash and stretch over time. See
Using Objects as Bones (page 1–387) .
Link Display
You can use Display Links and Link Replaces
Object to display the links instead of the object.
These settings are found in the Link Display
rollout on the Display panel. This can be useful
if you have a geometrically intensive hierarchy to
animate. The interactive v iewport response w ill be
much quicker 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 m a ke
changes to only one node, to change the animation
oftheentirechain.
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 con trol for posing the
upper b ody. It is not necessar y to use I K for ever y
character animation task. Using the HI IK solver
allows you to jump back and for th easily between
FK and IK.
How to Apply an IK S olver
YoucanapplyanIKsolverwhenyoucreatea
Bones system, or from the Animation menu:
•
Bones creation (page 1–381)
When you create bones, turning on the Assign
to Children option lets you apply an IK solver
immediately. Default=Off.
• You can apply the IK solver to a part of the
skeleton using Animation menu > IK Solver .
YoumustselectthenodewhereyouwanttheIK
chain to start, then choose Animation menu
> IK S olvers and select the solver. Then click
the n ode where you want the chain to end. The
chain will be created between the pivot points