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462 Chapter 12: Animation
In the top row, the ball is independent of the lamp. In the
bottom row, the lamp head is bound to the ball’s position.
Setting Binding Options
You can bind an object by position, orientation, or
both. Once an object is bound you can set binding
axes, weight, and whether the binding is absolute
or relative.
Bind Position—Causes an object to attempt to
maintain its location or to match the location of a
follow object.
Bind Orientation—Ca uses an object to attempt to
maintain its rotational orientation or to ma tch the
orientation of a follow object.
Relative—Changes how an object reacts to a bound
follow object. See the following discussion about
binding an object to a follow object.
Axis and Weight—Set these options to control
which axes are affected by the binding and the
binding’s influence over other bindings in the
kinemat ic chain.
Binding an Object to the World
You can bind an object to the world if you want the
object to hold its position and orientation as long
as possible during I K operations.
If you are animating a wa lk ing figure you want
one foot to remain in place while you position the
other foot. Without binding, t he whole hierarchy
would have a tendency to slide around when you
attempt to position a foot. Binding both feet to
the world ensures that the unselected foot stays in
place while you position the other foot.
B inding an Object to a Follow Obj ect
You can bind a selected object in your hierarchy
to any other object that is not a descendant of the
selected object. This other object is called the
follow object.
The behavior of the bound object varies depending
on the state of the Relative buttons next to the bind
options.
• WhenRelativeisinactive,theboundobject
tries to match the exact position and orientation
of its pivot point to the position and orientation
of the follow object’s pivot poin t.
• When Relative is active, the bound object
mimics any changes in position or rotation of
thefollowobjectbutdoesnottrytomatchit
exactly.
You might want to animate a figure that always
points to another object. Bind the hand of t he
figure to the other object with Relative act ive. Turn
IKon,andasyoumovetheobject,thehandand
arm of t he figure move to point at it.
Unbinding Obj ects
Ifyoudecidethatyoudonotwantanobjecttobe
bound you can either turn off the Bind O rientation
and Bind Position boxes, or unbind the object
from its follow object.
• If you turn off the binding options, you disable
theeffectofbindingwithoutremovingthe
binding to a follow object. This method is
handy if you decide to reposition a follow object
after you have bound an object to it.