9

Animating with Applied IK 481
IK structure
Results of animating the box and IK structure
B ehavi or of Objects in IK Mode
As you mov e and rotate objects using interactive
IKyounoticethatsomeobjectsmightnotbeable
to move or rotate about all axes. This is because
the objects are constrained by the joint p a rameters
you have set. If the joint parameters specify that
motion cannot occur in a cer t ain axis, the end of
the chain will not move.
B ehavi or of R oot Objects in IK M ode
An option on the Inverse Kinematics panel (page
3–830) of the Preference Settings dialog enables the
special case of moving and rotating root objects
when IK mode is on. The name of this control is
Always Transform Children Of The World.
While you are transforming an end effector using
IK mode, the settings for the root object’s joint
parameters are used and the root object does not
move w ith respect to the World. If you select the
root object, its joint parameters are released and
you c an transform the root object.
If you decide you want root objects to always use
theirjointparameters,youcanturnofftheAlways
Transfor m Chi ldren Of The World option.
Single, unlinked objects are hierarchies of one. An
unlinked object is its ow n root and is a lso a child
of the World. Turning Always Transform Children
of the World will prevent you from transforming
single objects in IK mode.
Animating with Applied IK
Select the end of a hierarchy > Hierarchy panel > IK > Set
object parameters such as Bind to Follow Object > Apply
IK.
Ap plied IK requires you bind one or more parts
of your IK st ructure to animated follow objects.
Once bound, you can select any object in your
kinematic chain and click Apply IK. This calculates
the IK solution for each frame of the animation
and places transform keys for every object in the
IK chain.
The A pply IK method of animation works best
when you want objects in the kinematic chain to
matchthemotionsofotherobjectsexactly.
Tip: Applied IK is a feature carried over from the
earliest version of t he software. It is recommended
that you explore the IK Solver methods first, and
only use Applied IK if you find the IK Solvers won’t
satisfy your needs.