3ds Max 2012 Bible - Kelly L. Murdock [407]
To create a bones system, select Create⇒Systems⇒Bones IK Chain, click in a viewport to create a root bone, click a short distance away to create another bone, and repeat this a few more times. Each subsequent click creates another bone linked to the previous one. When you're finished adding bones, right-click to exit bone creation mode. In this manner, you can create a long chain of bone objects all linked together.
These bones are actually linked joints. Moving one bone pulls its neighbors in the chain along with it. Bones can also be rotated, scaled, and stretched. Scaling a bones system affects the distance between the bones.
Caution
Bones should never be scaled without the XForm modifier applied, or all animation keys will behave erratically. •
To branch the hierarchy of bones, simply click the bone where you want the branch to start while still in bone creation mode. A new branching bone is created automatically. Click the Bones button again to create a new bone. Then continue to click to add new bones to the branch.
Figure 38.1 shows the rollouts that are available for creating bones.
FIGURE 38.1
The Bone rollouts let you specify which bones get assigned an IK Controller.
Assigning an IK Solver
When you first create a bone chain in the IK Chain Assignment rollout of the Create panel, you can select from four IK Solvers: History Dependent, IKHISolver, IKLimb, and SplineIK Solver. You can assign each of these solver types to children and to the root bone using the available options. You need to select both the Assign to Children and the Assign to Root options to assign the IK Controller to all bones in the system. If the Assign to Children option is deselected, then the Assign to Root option is disabled.
Note
Each of these IK Solvers is presented later in this chapter. •
Setting bone parameters
The Bone Parameters rollout (also in the Modify panel) includes parameters for setting the size of each individual bone, including its Width and Height. You can also set the percentage of Taper applied to the bone.
Tip
Because bones are simple geometry objects, you can apply an Edit Poly modifier to it and edit the bone shape to be whatever you'd like. Custom bone geometry doesn't always work with the Bone Tools. •
Fins can be displayed on the front, back, and/or sides of each bone. For each fin, you can specify its size and start and end taper values. Including fins on your bones makes correctly positioning and rotating the bone objects easier. Figure 38.2 shows a simple bones system containing two bones. The first bone has fins.
FIGURE 38.2
This bone includes fins that make understanding its orientation easier.
At the bottom of the Bone Parameters rollout is an option to Generate Mapping Coordinates. Bones are renderable objects, so this option lets you apply texture maps to them.
Tutorial: Creating a bones system for an alligator
To practice creating a bones system, you'll take a trip to the Deep South to gator country. The main movement for this gator is going to be in its tail, so you need the most bones there. The front legs are smaller and can be controlled with only two simple bones. You also won't worry about fingers.
To create a bones system for an alligator, follow these steps:
1. Open the Alligator bones.max file from the Chap 38 directory on the CD.
This file includes an alligator model created by Viewpoint Datalabs.
2. Select Create⇒Systems⇒Bones IK Chain, and in the IK Chain Assignment rollout, select IK Limb from the IK Solver drop-down list. Then set the Width and Height values to 10 and enable all the bone fins and