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5.Repeat Step 4 for the left arm.

6.Click the Select Objects button on the main toolbar to exit Bones mode, and select and name each bone object so it can be easily identified later.

Figure 35-3 shows the completed bones system for the puppet. You can select the bones at the end of each chain and move it to see how the inverse kinematics solution works.

Figure 35-3: This bones system for a puppet was easy to create.

Using the Bone Tools

After you’ve created a bones system, you can use the Bone Tools to edit and work with the bones system. You access these tools from a panel that is opened using the Character Bone Tools menu command. Figure 35-4 shows this panel of tools that includes three separate rollouts: Bone Editing Tools, Fin Adjustment Tools, and Object Properties.

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Figure 35-4: The Bone Tools palette includes several buttons for working with bones systems.

Reordering bones

You can use the transform buttons on the main toolbar to move, rotate, and scale a bone along with all its children, but if you want to transform the parent without affecting any of the children, you need to open the Bone Tools panel. Bone Edit Mode lets you move and realign a bone without affecting its children.

Clicking the Remove Bone button removes the selected bone and reconnects the bone chain by stretching the child bone. If you hold down the Shift key while removing a bone, the parent is stretched. Clicking the Delete Bone button deletes the selected bone and adds an End bone to the last child.

Caution	Using the Delete key to delete a bone does not add an End bone, and the bone chain does
	not work correctly with an IK Solver.

If a bone exists that isn’t connected to another bone, you can add an End bone to the bone using the Create End button. The bone chain must end with an End bone in order to be used by an IK Solver.

The Connect Bone button lets you connect the selected bone with another bone. After clicking this button, you can drag a line from the selected bone to another bone to connect the two bones.

Use the Reassign Root button to reverse the chain and move the End bone from the parent to the last child.

Refining bones

As you start to work with a bones system that you’ve created, you may discover that the one long bone for the backbone of your monster is too long to allow the monster to move like you want. If this happens, you can refine individual bones using the Refine button. This button appears at the bottom of the Bone Tools section of the Bone Editing Tools rollout.

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Clicking the Refine button enables you to select bones in the viewport. Every bone that you select is divided into two bones at the location where you click. Click on the Refine button again to exit Refine mode.

Coloring bones

Bones, like any other object, are assigned a default object color and can be applied materials from the Material Editor. For each separate bone, its object color can be changed in the Modify panel or in the Bone Tools panel.

You can also apply a gradient to a bone chain using the Bone Tools palette. This option is available only if two or more bones are selected. The Start Color is applied to the chain’s head and the End Color is applied to the last selected child. The colors are applied or updated when the Apply Gradient button is clicked. Figure 35-5 shows a long spiral bone chain with a white-to-black gradient applied.

Figure 35-5: A white-to-black gradient applied to this spiral bone chain

Adjusting fins

The Fin Adjustment Tools rollout includes the same parameters as those found in the Bone Parameters rollout. You can specify the dimensions and taper of a bone and its fins. But you can also specify that the parameters are applied using Absolute or Relative values. Relative values are based on the parameters of the bone that is above the current bone in the chain.

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This rollout also includes Copy and Paste buttons that you can use to copy the bone parameters from one bone to another.

Making objects into bones

You can make any object act like a bone. To make an object into a bone, you need to open the Object Properties rollout in the Bone Tools panel. The Object Properties rollout, shown in Figure 35-6, includes a setting for Bone On/Off. If enabled, the object acts like a bone. When the Bone On/Off option is enabled, then the remaining Bone controls become available. The Auto-Align option causes the pivot points of adjacent bones to be aligned automatically. The Freeze Length option causes a bone to keep its length as the bones system is moved. If the Freeze Length is disabled, you can specify a Stretch type. None prevents any stretching from occurring, and Scale changes the size along one axis, but Squash causes the bone to get wider as its length is decreased and thinner as it is elongated. You can also select a stretch axis and whether to Flip the axis.

Figure 35-6: Use the Object Properties rollout to make any object act like a bone.

You can use the Realign button to realign a bone; click the Reset Stretch button to normalize the stretch value to its current value.

Tutorial: Making bones automatically

Models such as vehicles and life forms have a natural link order and often come already linked. When you make a linked model into bone objects, the model inherits the benefits of a bones system. In this tutorial, we import a structured primitive man created in the preceding chapter and make him a bones systems.

To make the primitive man a bones system, follow these steps:

1.Open the Primitive man bones.max file the Chap 35 directory on the CD-ROM.

2.With all objects selected, choose Character Bone Tools to open the Bone Tools panel.

3.In the Object Properties rollout, select the Bone On and the Auto Align options. Select also the Squash option.

4.In the Link Display rollout of the Display panel, click the Display Links check box to see the links between the bones.