2009

For one-way wires, the Expression box for the controlling parameter is

unavailable, since there is no Wire controller assigned to it.

For two-way wiring, both transfer expression text boxes will be enabled. It is

possible for the user to supply transfer expressions for the two parameters that

are not inverses of one another, but this is of course discouraged, since the

relationship of the parameters will be different depending on which one is

changed first.

Hierarchies and Kinematics

When animating characters, mechanical assemblies, or complex motion, you

can simplify the process by linking objects together to form a

hierarchy on

page 8002 or chain. In a linked chain, the animation of one member can affect

some or all of the others, making it possible to animate a number of objects

or bones at once.

The term

kinematics on page 8021 describes the movement or animation of the

chain. There are two types of kinematics:

■ With

forward kinematics on page 7987 (FK) , you transform a parent object

to move its descendants (its children, their children, etc.).

■ With

inverse kinematics on page 8016 (IK), you transform a child object to

move its ancestors (its parent and so on up the chain). You can also use

IK to make an object “stick” to the ground or another surface, while

allowing the chain to rotate off the pivot of that object.

Forward kinematics is the most straightforward method for animating

hierarchies. Inverse kinematics requires more setup than forward kinematics,

but is more intuitive for complex tasks such as character animation or intricate

mechanical animation.