9

468 Chapter 12: Animation
The hoof (a child) has precedence over the leg (its parent).
Foranygivenpositionofanendeffector,thereare
many possible IK solutions.
The three joint precedence controls in the Object
Parameters rollout are:
Precedence—Sets joint precedence manually.
Child->Parent—Automatically sets joint precedence
to decrease in value from child to parent.
Parent->Child—Automatically sets joint precedence
to decrease in value from parent to child.
Determining Or der of Calcula tions
You control the HD IK solution by setting joint
precedence to determine which joints contribute
the most to the HD IK solution and which joints
contribute the least.
• Jointswithhighprecedencevaluesare
calculated first, and contribute more motion
to the HD IK solution.
• Joints with low precedence va lues are calculated
last and contribute the least motion to the HD
IK solution.
• Joints w ith equal precedence values are
calculated by order in the hierarchy. Joints
closertotheendeffectorarecalculatedfirstand
joints closer to the root are c alculated last.
Of all of the joint parameters, Joint Precedence is
the most subtle.
See also
Using Default Joint Precedence (HD Solver) (page
2–468)
Choosing Child-to-Parent Precedence (HD Solver)
(page 2–469)
Choosing Parent-to-Child Precedence ( HD Solver)
(page 2–470)
Setting Precedence Manually (HD Solver) (page
2–471)
Using Default Joint Precedence
(HD Sol ver )
Thedefaultjointprecedenceissuitableformany
HD IK solut ions. It assumes that joints closest
to where a force is applied (the end effector) will
move more than joints farther from the force.
Thedefaultjointprecedenceisavalueof0for
every joint: all joints have the same precedence
value. This default starts calculations with the end