8

384 Chapter 5: Creating Geometry
Bones c an be renderable.
Obj ect P roperties for B on es
In addition to visual properties, bones have
behavioral properties. The controls for these are
located on the
Bone To ols floater (page 1–388) .
You can use these controls to turn other kinds of
objects into bones.
Using Constr ai nts with B ones
Yo u c a n a p p l y constraints (page 2–375) to bones
as long as an IK solver or method is not cont rolling
thebones. IftheboneshaveanassignedIK
controller, you can constrain only the root of the
hierarchy or chain. However, applying position
controllers or constraints to a linked bone can
cause unde sirable effects, such as breaking of the
bone chain.
The “nub” bone at the e nd of the chain has a Spring
controller applied to it. The Spring controller is connected
to an animated sphere.
Right: The sphere’s movement breaks the bone chain.
To avoid this problem, don’t apply position
controllers directly to child bones. Instead, create
an IK chain and apply the controller to the IK
chain’s end effector.
A IK chain has been applied, connecting the end nub to its
parent bone. The IK chain’s end effector is connected to
the b all by a Spring controller.
Right: Now when the sphere moves, the IK chain prevents
the bones from breaking.
Constraints and controllers that affect orientation
only, such as Orientation or Look At, do not
present this problem when applied to child bones.