TYPE: Object State
TITLE: Bones (Bone Chains) Operation

The Bones operation lets you interactively draw and manipulate bone chains
before animating. For a complete list of the mouse controls at all times, please
refer to the status line at the bottom of the Houdini window. The common tasks
are described below.

DRAWING BONE CHAINS

To draw a new bone chain, left-click repeatedly in the viewer to position the
joints, then right-click to finish. The bone chain will be created using the
type specified in the "Kinematics" option located directly above the viewport.
For "Follow Curve" bone chains, expect to be prompted for a curve object.  To
start drawing from any object, Shift+Left click on the object that you wish to
extend from.

To change bone chain kinematic types, first choose the "Remove Kinematics"
option from the Ctrl+Right mouse menu. Select the bones that you wish to remove
kinematics for, then right-click to complete. Now, change your Kinematics option
to the new type. Finally, choose the "Add Kinematics" option from the Ctrl+Right
mouse menu. Houdini will prompt you for the required object selections to
perform the operation.

CHOOSING THE PARENT FOR A NEW BONE CHAIN

To select a parent, Ctrl+Middle click on the desired object. The new bone chain
that you draw after this will have this object as its parent. To reset back to
no parent, Ctrl+Middle click on emptiness in the viewer, away from all objects.

SPLITTING A BONE

To divide a bone into two, Ctrl+Left click on the desired bone.

MANIPULATING JOINTS

A Joint handle is created for all the currently displayed bones when you enter
the Bones operation. To adjust the position of any joint, click or drag the
square handles that you see positioned at the tips of bones. If you do not wish
to accidentally click on these squares, toggle them off by pressing the Joint
handle button in the left toolbar, or right-click on any Joint handle and toggle
its Display Handle option. To manipulate several handles at the same time,
select them by holding SHIFT key.

The Joint handle operates in several modes. Right-click on any of the square
handles to see the complete list. The translate handle manipulates the joint
position. The rotate handle spins the bone about its origin. The spider handle
adjusts the lengths of the bones connected at the joint and moves the joint
along the average normal of those bones.

WHAT TO DO NEXT

Before binding the bones to the skin with Capture Geometry, you may want to
adjust the capture regions with Edit Capture Regions, then mirror the bone chain
with Mirror if you need a symmetrical limb. After Capture, use Pose to animate
the bones and see if any capture weights need tweaking. If so, experiment with
editing capture regions (procedurally) or with Paint/Edit Capture Weights.
Mirror Capture Weights will come in handy if you have painted or hand-edited the
weights of one limb and want them reflected automatically to save time.

See also: Capture(capturegeometry), Pose
