Adobe Fireworks CS4 v.10 65011677 Manuale Utente

Inverse Kinematicss, or IK, is 

one of the staples of sophisticated 

animation techniques. IK means to 

apply an underlying skeleton to a 

shape that defines the connections 

and relationships between different 

elements of that shape. When IK 

effects are applied to the image of a 

tree, moving the branch causes the 

leaves to flutter.

Sound complicated? It is actually quite 

simple: all you need to do is to use the 

new Bones tool in Flash CS4 to draw 

links between the objects you want to 

move in relation to each other.  

A few clicks opens up the considerable 

creative potential of this complex 

animation effect—without requiring 

any programming.

Inverse Kinematics

 Pushes the Envelope of Flash Animation

Adobe Flash CS4 Professional—Reviewer’s Guide 11

Try it: Link objects together with the Bones tool
1.  Choose File > Open, and then navigate to the Flash_CS4_RG_Assets folder. Select and 

open the file named craneArm.fla.

On the stage you can see several symbols, each making up a separate section of a crane. 
2.  Select the Bones tool   and click and drag from the base of the crane to the very top, 

where it connects to the next arm of the crane. This action “links” the first two symbols 

together.

3.  Position your cursor at the precise point where your first “joint” ends, and then click and 

drag to the right to create a second link, this time connecting the arm to the ropes.

4.  With the selection tool, click and drag on the hook, which appears at the end of the rope. 

As you move this one symbol, notice all of the other symbols moving as well—each 

movement defined by the skeleton that you’ve created with the Bones tool.

   

   

Take a look at the Timeline. You’ll notice a new layer was created, named Armature_1.  

This layer keeps track of the skeleton that you’re creating, which controls how the symbols 

interact with each other.

5.  Click on the Armature layer to select it. In the Properties panel, you can see a section 

called Options, where you’ll find the Type setting set to Authortime. This setting allows 

you to position your artwork on the stage, according to the defined armature. Switch the 

Type setting to Runtime. This tells Flash to enable the armature settings when the Flash 

file is played in Adobe Flash Player.

Left: Connecting the base of the crane to

the arm at the top in Step 2. Center:

Connecting the arm of the crane to the 

ropes in Step 3. Right: Moving the hook of

the crane in Step 4.

Click above to see how the armature is created.