All IK chains for the current figure are displayed at the bottom of the Hierarchy Editor, shown in Figure 1.

This dialog box is opened with the Window, Hierarchy Editor menu command. You can select IK chains by using the Hierarchy Editor.

All the bones between these two selected bones are collectively called an IK chain. In order for Inverse Kinematics to work, you need to select a parent object (the root object) and one of its children objects (the goal object) connected in a chain. The trick is to learn when to use IK and when to disable it. This time the upper thigh moves easily and the foot moves along with it. Now try disabling IK and moving the upper thigh element again. Quick Tip: You should enable and use IK if you need to place the end of an IK chain such as a hand or a foot in a specific location, but for general body movement and poses, you can disable IK. The upper thigh element might twist a little, but because it is part of the IK chain, it won't move out of place unless the end of the IK chain, the foot, is moved. When Poser first loads, select the default figure's Left Thigh object and try to move it with the Translate/Pull tool. To animate this sequence by moving only the upper thigh and upper arm bones would be difficult, but with Inverse Kinematics enabled, you can position the feet for the steps and the hand for the door handle and the remaining body parts just follow. For example, imagine a character walking across the floor and reaching for a door handle. The benefit of Inverse Kinematics is that it is often easier to animate characters by placing their hands and feet than placing their hips and shoulders. Inverse Kinematics works backwards by solving the shoulder's position as the hand is moved. For example, because the shoulder is connected to the arm bones, which are connected to the hand, you can use kinematic equations to determine the position of the hand as the shoulder moves.

Bone structures are a good example of a set of linked objects that can be defined using kinematic solutions. Kinematics is the physics behind the movement of linked objects. In this lesson, you learn how to create a new IK chain. We will offer step-by-step tutorials for each task, followed by projects that allow readers to apply each new skill. In the next few months, VFXWorld readers will develop the skills needed to create, render and animate scenes and projects using the amazing tools offered by Poser 7. This is the next in a new series of excerpts from the Thomson Course Technology book Poser 7 Revealed: The e frontier Official Guide.

Poser 7 review