8
438 Chapter 12: Animation
In the Parent Space group you can choose to
whether the IK goal or the start joint will be used
as the parent space for t he swivel angle. If IK
Goal is selected (which is the default), then the
Swivel Angle of the chain is defined in the parent
space of its goal. If Start Joint is chosen, then the
SwivelAnglewillberelativetotheparentspaceof
the sta rt joint. These two options allow a much
better control of the swivel angle on a chain with
two HI IK solvers. For example, the first solver on
theupperpartofachaincanuseaSwivelAngle
intheParentSpaceoftheStartJoint,whilethe
second IK solver on the lower part of the chain
uses the Parent Space of the IK Goal. In this c ase,
thechangeoftheSwivelAngleforonechainwon’t
change the orientation of the other one.
IntheThresholdsandSolutionsgroupyoucan
refine the IK solution. The Position Threshold sets
a limit in units of how far the goal can be moved
from the end effector, the Rotation does the same
in angle degrees.
TheSolutionsgroupIterationsisthemaximum
number of attempts the IK solution will perform
before g iving up.
If your IK animation seems to jitter, try increasing
the Iterations to 200. Increasing the Iterations wi l l
slow down the computational time, but should
produce better results.
Ma nipulator f or the S wivel Angle
You can adjust the swivel angle with
the spinner in this rollout, or you can adjust it
withamanipulator. Todoso,turnon
Select
and Manipulate (page 2–26)
.Theswivelangle
manipulator is displayed as a handle in the
viewports.
Swivel angle manipu lator.
Whenyoumovethemouseoverthemanipulator,
itturnsred. Atthispoint,youcandragthe
manipulatortochangetheswivelangle.TheAuto
Key button can be active while you do this.
You can also animate the swivel angle by using a
target object. Pick an object for the target, then
animating the object will animate t he swivel angle.
The sw ivel angle manipulator is a standard
plane
angle manipulator (page 2–29)
.TheHISolverhas
itsowncontrolsfordisplayingthismanipulator.
These are on the
IK Display Options rollout (page
2–439)
.
Procedure
To increa se t he precision of an IK s olution:
1.
Select the goal in an HI IK chain.
2. In the IK Solver Properties rollout increase the
Iterations to 200 in the solutions group.