[Figure 3-35] Using Limits prevents unnatural poses

Using Limits
Poser is aware of exactly how far each body part can actually bend in order to maintain a realistic pose, but you can also disable this option to allow body parts to move through one another. The Figure, Use Limits option is a toggle that you can enable or disable. When enabled, Poser restricts the movement of the body parts to realistic positions. For example, when dragging a figure’s arm straight up with the Use Limits option enabled, Poser prevents the arm from moving farther than the head, as shown in Figure 3-35. Limits also prevent the head from rotating all the way around.

You can set and edit limits by using the Parameter Settings dialog box. You can access this dialog box by clicking on the pop-up menu to the right of any parameter dial.

[Figure 3-36] Auto Balance center-balances figures

Using Auto Balance
Another helpful setting that can aid you in creating realistic poses is the Figure, Auto Balance option. This option, like Use Limits, is also a toggle button. When enabled, counter body parts are moved in order to maintain the centered weight of the figure. The pose, shown in Figure 3-36, was created by moving the right foot with the Auto Balance option enabled. Poser moved the top half of the figure to the right to counter the foot’s position.

Enabling Inverse Kinematics
Normally when you pose body parts, you position the objects by moving the parent object and having all its children follow. The children can then be moved independently. This method of positioning objects is called Forward Kinematics because it follows the hierarchy structure, but another method exists called Inverse Kinematics (IK). IK works by allowing the child object to control the position of the parent object.

You can enable or disable IK for each arm and leg using the Figure, Use Inverse Kinematics menu command. When enabled, IK lets you position a figure’s hand or foot and the rest of the body parts move to accommodate the motion.

By default, IK is enabled for the legs and disabled for the arms.

[Figure 3-37] Default chain break icons

Using the Chain Break Tool
IK chains aren’t the only elements that have control over other body parts. Actually almost all body parts are connected and can influence one another. If you drag an arm element far enough, the torso will move along with it, but you can use the Chain Break tool (L) to prevent the movement of connected elements.

If you select the Chain Break tool, several chain break icons appear on the figure in Document Window, as shown in Figure 3-37. These icons mark body parts that are prevented from moving with adjacent elements. By default, the head, hip, right, and left buttock elements have a chain break icon on them. This means that the head moves independently of the torso and the torso moves independently of the legs.

If you click an element with the Chain Break tool, you can place or remove these icons. For example, if you click the right and left collar elements, moving the arms will have no effect on the torso.

The chain break icon for the hip cannot be removed.