9

498 Chapter 12: Animation
hierarchy. IK Solvers are applied to the hierarchies
using the Animation menu.
When an HD IK Solver is applied to an IK chain
the Inverse Kinematics rollout displays the controls
described below.
The Inverse Kinematics rollout provides controls
for interactive and applied IK, as well as the
controls for the HD Solv er (history dependent).
UseApplyIKtocalculateanIKsolutionand
generate Transform keys (move, rotate) for all
objects in an IK chain (the IK chain must include a
follow object). By default, keys are created at every
frame.
• Applied IK requires that one or more parts of
your IK structure b e b ound to animated follow
objects. Once b ound, you can select any object
in your kinematic chain and click the Apply IK
button.
• TheApplyIKmethodofanimationworksbest
when you want objec ts in the kinematic chain
to match the motions of other objects exactly.
An example of this would be a mechanical
connection that should always appear to be
attached to the follow object.
Pr ocedur es
To use interactive IK:
1.
Build a hierarchy of objects.
If you w ant to use Bones, b e sure Assig n to
Children is not active when you create the
Bones.
2. Select the end of the chain.
3. Go to the Hierarchy p anel > IK button.
4. Scroll up to the Inverse Kinemat ics Rollout
5. Click Interactive IK.
6. Advance the time slider and move the end of
the chain.
7. Turn off Interactive IK when you want to do
forward kinematics.
To use a pplied IK :
1.
Add an HD Solver to your hierarchy .
2. Bind objects in your IK structure to follow
objects.
3. Animate the follow objects.
4. Select any object in the IK structure.
5. Click IK in the Hierarchy panel and expand the
Inverse Kinema tics rollout.
6. Click Apply IK.
Tip: Be sure your Start Frame and End frames
match the length of your animation.
Interfa ce
Interactive IK — Allows for IK manipulation of
hierarchies without applying an IK Solver or using
afollowobject.
Apply IK —Calculates the IK solut ion for each
frame of the animation and creates tr ansform
keys for e very object in the IK chain. A bar graph
appears on the prompt line to indicate progress
of the calculations.
Apply Only To K ey s—Solves the IK solution for
keyframes that already exist for one of the end
effectors.