2009

Using Default Joint Precedence (HD Solver)
The default joint precedence is suitable for many HD IK solutions. It assumes
that joints closest to where a force is applied (the end effector) will move more
than joints farther from the force.
The default joint precedence is a value of 0 for every joint: all joints have the
same precedence value. This default starts calculations with the end effector and
progresses up the IK chain until the base object is reached.
Using methods described in the following topics you can change the default
precedence values. You can also set your kinematic chain back to its default
precedence.
To reset the default joint precedence:
1 Select all objects in the kinematic chain.
2 On the Hierarchy panel, expand the Object Parameters rollout.
3 Set Precedence to 0.
NOTE Default joint precedence occurs whenever all joints in the kinematic
chain have the same precedence value. Assigning a value of 100 to all objects
in the kinematic chain is exactly the same as assigning a value of 0.
Choosing Child-to-Parent Precedence (HD Solver)
Child–>Parent precedence causes joints closest to where a force is applied (the
end effector) to move more than joints that are farther away from the force.
Like the default precedence, Child->Parent precedence produces a natural
result that is suitable for many IK solutions.
The difference is that Child−>Parent precedence assigns unique values to each
object in the kinematic chain (default precedence uses the value of 0 for every
object). Child−>Parent precedence is more flexible if you want to go back and
manually change precedence values.
3436 | Chapter 15 Animation