Using the Bone Tools

Within the Tools palette is a special section of tools for working with bones. The Bone tools, shown in Figure 26.1, are only activated when a bone layer is selected in the Layers palette. To create a bone layer, click the New Layer button at the top of the Layers palette and select the Bone option from the pop-up menu. Bone layers can hold sublayers. To add a layer to a bone layer, simply drag the layer and drop it on the bone layer in the Layers palette.

Adding Bones

With a bone layer selected, you can begin to add bones to the scene using the Add Bones tool (A). To add a bone, simply click and drag in the working area. Bones are triangular shaped, as shown in Figure 26.2, with a thick portion at one end tapering to a point at the opposite end. The thicker portion represents the jointed end or base of the bone and the pointed end represents the bone’s tip.

If you hold down the Shift key while creating a new bone, the new bone will be created at 45-degree increments.

Selecting Bones

After a group of bones is created, you can select the bone that you want to work with specifically by selecting the bone with the Select Bone tool (B). Bones will only be visible in the working area if the bone layer is selected in the Layers palette or one of the bone layer’s sublayers is selected. To select a bone, simply click it. The selected bone turns red. If you hold down the Ctrl/Cmd key while clicking, you can select multiple bones at once.

Naming Bones

The selected bone can be named using the empty field located in the Options bar at the top of the working area. The bone name can be used when writing scripts to reference the bone.

Anime Studio includes a preference that will automatically name every bone that is created. If you open the Edit, Preferences dialog box and enable the Auto-Name Bones and Shapes option, then every new bone is given a sequential number as its name. These numbers can be renamed with a more meaningful name if you select the bone layer.

Connecting Bones

If you drag to create another bone with the Add Bones tool (A) when an existing bone is selected, the new bone will be connected automatically to the existing bone as its child. Child bones can move independently of their parent, but when a parent bone is moved, the child moves with it.

By creating several bones in succession in a straight line, you can quickly create a linkage of bones that resembles a spine, as shown in Figure 26.3.

Translating and Rotating Bones

Once a bone is created, you can move and rotate it to get it into the correct position using the Translate Bone tool (T). If you click the selected bone at its thick base, then the entire bone will move while maintaining its current orientation, but if you click near the bone’s tip, you can drag to change the bone’s orientation and even the bone’s length.

If you hold down the Shift key while moving a bone, the bone will be constrained to move only in the vertical or horizontal directions. If you drag a bone tip with the Shift key held down, then the bone’s orientation will snap to 45-degree increments.

If you hold down the Shift key while dragging a child bone, the bone’s movement will be constrained to the vertical and horizontal axes of the parent bone. This provides an easy way to align children bones at right angles to their parents.

If you want to rotate the selected bone without changing its length, you can use the Rotate Bone tool (R). This tool lets you rotate the bone regardless of where you click on the bone. Holding down the Shift key lets you rotate the bone at 45-degree increments.

Nudging Bones

If the Translate Bone tool (T) is selected, you can hold down the Ctrl/Cmd key and press the arrow keys to nudge the selected bone a small distance in the direction of the pressed arrow. Holding down the Ctrl/Cmd key with the Shift key nudges the bone a larger nudge distance. The actual nudge distance is 1 pixel for a short nudge and 10 pixels for a large nudge.

Reparenting Bones

If you create a parent-child connection that isn’t correct, you can fix the linkage with the Reparent Bone tool (P). To use this tool, select a bone and click the tool. All parented bones in the current layer are identified by red arrows that point from the child bone to its parent, as shown in Figure 26.4. If you click a bone other than the one that is selected, the selected bone becomes the new parent to the original selected bone.

Copying and Pasting Bones

When a bone or multiple bones are selected in a bone layer, you can use the Edit, Cut (Ctrl/Cmd+X) or Edit, Copy (Ctrl/Cmd+C) menus to copy a duplicate of the selected bones. These copied bones can then be pasted onto another bone layer using the Edit, Paste (Ctrl/Cmd+V) command.

Deleting Bones

To delete a selected bone, simply press the Delete key or the Backspace key. If a parent bone is deleted, then all its children are also deleted.

Creating a Skeleton

Before you create a set of bones, it is helpful to have visible the layer of the objects that the bones will be controlling so that you can line the bones up correctly. Bones can control any type of layer including vectors, images, and 3D layers. To add a layer to a bone group so that it can be controlled by the bones, simply drag the layer and drop it on the bone layer in the Layers palette. By creating a linkage of bones that are parented, you can create a skeleton that will give you control over all the parts of the drawing layer.

To create a skeleton of bones to control a lizard character, follow these steps:

1.	Open the Lizard with bones.anme file from the Chapter 26 folder on the CD. This file includes a single vector layer with a lizard stroke.
2.	Click the New Layer button at the top of the Layers palette and select the Bone option from the pop-up menu to create a new bone layer.
3.	With the bone layer selected in the Layers palette, click the Add Bone tool (A) and click the top of the lizard’s head and drag to the lizard’s neck to create a bone. Continue the bone chain that runs down the lizard’s back and tail by clicking and dragging to create about seven bones.
4.	Click the Select Bone tool (B) and select the head bone; then select the Add Bone tool (A) again and click and drag to create two arm bones. The new bone is automatically connected to the tip of the head bone. Repeat this step for the opposite arm.
5.	Select the Select Bone tool (B) and choose the second bone, whose tip is located where the legs are connected. Then choose the Add Bone tool (A) again and create three bones that run the length of the leg. Then repeat this step for the opposite leg. Figure 26.5 shows the resulting bone structure over the lizard. Figure 26.5. A skeleton of bones for the lizard. [View full size image]
6.	Select the vector layer that contains the lizard drawing and drop it on the bone layer in the Layers palette.
7.	Select the Manipulate Bone tool (Z) and select and drag the created bones around to deform the lizard.