9.5.2

766 • CHAPTER 17
OBJECT MANAGER • 767
Kinematic
You can use this tag to specify angle restraints for the object when using inverse kinematics (IK).
For example, a real knee can bend through about 160° only. Angle restrictions can also be useful for
preventing objects from intersecting each other.
Specify the restraint by entering Minimum and Maximum values for Heading (H), Pitch (P) and Bank
(B). You can also specify a damping factor. The higher you set Damping, the stiffer the joint becomes.
Parts of the IK chain with a lower damping factor will move more readily.
The HPB angles refer back to the object’s parent system, i.e. if the object is in
a hierarchy, the parent system takes the place of the world system. One easy
way to set the values is to select the object and read its coordinates in the
Coordinate manager. You can then add and subtract to calculate the minimum
and maximum values for the Kinematic tag.
Example
 Change into View 2 (XZ plane) and create a Bone object (Objects >
Deformation > Bone). Move the view so that the bone object is near the
bottom of the view (to move the view, hold down the ‘1’ key and drag within
the viewport).
 Click the X-axis icon on the top toolbar to lock the X-axis. Ctrl-drag from
the bone’s orange handle (at the top of the bone) to drag out a new bone.
Release the mouse button once the new bone is about the same size as the
original bone.
 Ctrl-drag a new bone out of the second bone until it is about the same size
as the other two. The advantage of dragging out bones in this way is that the
hierarchy is created automatically in the Object manager.
 Create two nulls (Objects > Null Object). Move one of the nulls along the
Z-axis (drag its blue handle) to the end of the bones chain and rename it Handle.
Make Handle a child of the last bone in the Object manager. (Open the bone
hierarchy by clicking the small plus icons as required.)