Adobe Flash Professional CS6 Adobe Flash Professional CS6 Classroom In A Book | Page 170

Articulated Motion with inverse Kinematics
When you want to animate an articulated object (one that has multiple joints), such
as a walking person, or as in this example, a moving crane, Flash Professional CS6
makes it easy to do so with inverse kinematics. Inverse kinematics is a mathemati-
cal way to calculate the different angles of a jointed object to achieve a certain
configuration. You can pose your object in a beginning keyframe, and then set a
different pose at a later keyframe. Flash will use inverse kinematics to figure out the
different angles for all the joints to get from the first pose to the next pose.
Inverse kinematics makes animating easy because you don’t have to worry about
animating each segment of an object or limb of a character. You just focus on the
overall poses.
defining the bones
The first step to create articulated motion is to define the bones of your object. You
use the Bone tool (
) to do that. The Bone tool tells Flash how a series of movie
clip instances are connected. The connected movie clips are called the armature,
and each movie clip is called a node.
1 In your 05working_copy.fla file, select the crane layer. Lock all the other layers.
2 Drag the cranearm1 movie clip symbol from the Library panel onto the Stage.
Place the instance right above the rectangular crane base.
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