Opening the Hierarchy Editor
You can open the Hierarchy Editor, shown in Figure 3-41, using the Window, Hierarchy Editor menu command. It includes a list of all the items that are included in the current scene indented to show the parent-child relationships of the scene items. The default figure and the Library figures all have a pre-defined hierarchy.

Selecting View Options
The options at the top of the Hierarchy Editor Window let you select which types of items to make visible, including Figures, Cameras, Parameters, All Parameters, Props, Deformers, and Lights.

To the left of each item name are three icons. The first icon is a small arrow. By clicking this icon, you can expand or collapse the children listed underneath the current item. For example, the Forearm is a child of the Shoulder element and clicking the collapse icon hides the Forearm element and all its children and changes the icon to a sideways arrow.

Hiding Items
The second icon is the Visibility icon. Clicking this icon hides the selected item in the Document Window, but not any of its children. The third icon identifies the item. For example, all body parts are identified with a hand icon, all props have a ball icon, the entire scene (called the Universe) has a world icon, the Body object has a stick figure, lights have a light bulb icon, cameras have a camera icon, deformers have a small magnet, IK chains has a chain link icon, and parameters have a wheel icon.

Selecting and Renaming Items
Selecting an item in the Hierarchy Editor automatically highlights the item and selects the same item in the Document Window. Double-clicking an item title in the Hierarchy Editor selects the item’s name in a text field where you can type a new name for the selected item. You can also delete certain items, including props and figures.

The Hierarchy Editor is also a convenient place to quickly delete multiple objects. Individual body parts, cameras, and the ground plane cannot be deleted.

Setting a Figure’s Parent
By default, all figures in the scene are children to the Universe item, which is the top (or root) item in the scene, but you can change the figure’s parent using the Figure, Set Figure Parent menu command. This command causes the Figure Parent dialog box, shown in Figure 3-42, to open. From within this dialog box, you can select a new parent for the figure. For example, you might want to parent a figure to a bicycle or an elevator prop.

You can parent figures only to the items listed in the Figure Parent dialog box, including lights, cameras, and props.

A new figure parent can also be assigned using the Hierarchy Editor. To do this, simply select and drag the Figure title to the item that you want to be its parent and the hierarchy will be reordered to show the change.

Setting an Item’s Parent
Figures aren’t the only items that can be assigned a new parent. Most items, including elements, cameras, and props, can be made children objects. To assign a new item to be the selected item’s parent, select the Object, Change Parent menu command. This causes the Choose Parent dialog box to appear, which is similar to the Figure Parent dialog box shown previously, where you can choose the item to be the parent.

You can also drag the item’s title in the Hierarchy Editor and drop it on the item that you want to be its parent. A third way to choose an item’s parent is to click the Set Parent button in the Properties palette for the selected item. This opens the Change Parent dialog box.

The Hierarchy palette is also very helpful in rigging figures and creating Inverse Kinematics chains. The buttons at the bottom of the Hierarchy palette are covered in Chapter 12, “Rigging a Figure with Bones.”