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476 Chapter 12: Animation
of multiple follow objects or end effectors and their
priority in solving the IK solution. The higher the
relative Weight value, the higher the priority.
The Weight settings are relative; there’s no point in
using them if there ’s only one follow object or end
effector in your IK hierarchy.
However, if you have a single HD IK chain with
both Position and Rotation end effectors on a
single joint, you can give them different weights
to give priority to either the position or rotation
solution.
You can adjust the Weight for multiple joints.
Select two or more objects in the hierarchy, a nd
the Weig ht value represents the commonality of
the selec tion set.
Note: Differences in the Weight values only have an
effect w hen there is no solution that satisfies two
or more opposing end effectors in the chain. In
this case, the end effector w ith the greatest weig ht
"wins."
Bind To Follow Objec t group
Controlstobindandunbindanobjectinan
inverse kinematic chain to a follow object .
(La bel)—Displaysthenameoftheselectedfollow
object. Displays the word "None" if no follow
object is set.
Bind—Bindsanobjectinaninversekinematic
chain to a follow object.
Unbind—Unbinds the selected object in a HD IK
chain from its f ollow object.
Pr eced ence (HD Sol ver )
Make a selec tion with an HD IK Solver applied. > Hierarchy
panel > IK > Object Parameters rollout > Precedence
Youcanusethethreejointprecedencecontrolsto
alter how the IK Solution is calculated.
Thedefaultjointprecedenceis0.Thisissuitable
for many 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.
Child->Parent—values are calculated by assuming
the root of the entire hierarchy has a precedence
value of 0 and each child has a value equal to 10
times its depth from the root. In a four-object
hierarchy st arting with the root, the va lues would
be 0, 10, 20, and 30.
Parent->Child—values are calculated by assuming
the root of the entire hierarchy has a precedence
value of 0 and each child has a value equal to 10
times its depth from the root. In a four-object
hierarchy st arting with the root, the va lues would
be 0, -10, -20, and -30.
• 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 assig ning a value of 0.
• An IK chain of three objects with precedence
values of 0, 30, and 200 would have the same
solutioniftheprecedencewerechangedtobe
1, 2, and 3.
Procedures
To assign a precedence value to an object manually:
1.
Select an object in an H D IK Chain.
2. Open the O bject Parameters rollout in the
Hierarchy panel.
3. Enter a value in the Precedence field.