Intro to Inverse Kinematics
Creating IK Shapes
Click to start parent bone
Drag to extend bone
Release to complete bone
Figure 13.12 Adding bones within a shape is very
similar to adding bones between symbol instances,
except that all the bones stay within the same shape.
Creating IK Shapes
An IK armature inside a shape works
something like a hand in a sock puppet.  e
armature can be linear or branching or a
combination of the two styles.  e steps for
creating the chain or branches are quite simi-
lar to those for connecting symbols.  e dif-
ference is that you place all the bones within
a single shape. You can use a merge-shape,
drawing-object, or primitive-shape, with or
without a stroke. Once you add IK bones to
the shape, Flash converts it to a new type of
shape, an IK shape.
To combine linear and branching
armatures inside a shape:
1. Using Flashs drawing tools, on the Stage,
create a shape to which you want to add
an internal armature structure.
For this task, draw a rounded rectangle,
making it fairly long and narrow (see
Chapter 2). Youll create an armature that
has two linear chains that branch from a
central point, allowing the shape to curl up
or down from either end, the way a worm
might wriggle from either end, or the way
that the arms extending from the torso of a
cartoon character might bend up or down.
2. In the Tools panel, select the bone tool.
3. To begin drawing the  rst bone in the
chain (the parent bone), position the
pointer over the shape.
4. Click at the spot where you want the
armature to start—for example, the
center of the rectangle (Figure 13.12).
Flash places the head of the parent bone.
e head and tail points of each bone
create points of rotation (places where
the shape can bend).  e shape as a whole
pivots around the head of the parent bone
in the chain.
continues on next page
Creating IK Shapes
Chapter 13
Click to start branching bone
Drag to extend bone
Release to complete bone
Figure 13.13 To begin the branching bone, position
the pointer over the head of the parent bone in the
existing chain, then drag to the left.
Figure 13.14 Your fi nished shape has two branches
that start from the center of the shape. Each branch
then continues with a linear chain of IK bones.
This arrangement allows the two halves of the
rectangle to curve independently, thus creating