The Handle Object is an IK tool designed for manipulating bones that conform to multiple end affectors. In contrast with regular IK which only has 1 end affector (or goal object), this method allows for several end affectors per bone. Furthermore, the bones need not be a chain. Any setup, including branches, are handled.
One typical example is the use of motion capture data. In higher-end systems, you typically have a cloud of marker positions and a skeleton to be driven by it.
This Handle Object works in tandem with the Handle CHOP (see for example). The following setup is commonly used: Given a hierarchy of bones, attach one or more Handle objects to specific locations on each bone object (as children). Assign each handle a target in space to follow. Create a Handle CHOP which collects this information and calculates the rotation channels for the bones. Export these values back to the bones.
The end affector object.
A translational offset from the origin of the parent.
Used to weigh multiple affectors attached to each bone.
Describes how much a handle will affect bones higher in its chain.
This option specifies that the handle object only affect the twist rotation of its parent bone, not all three rotations.
Rotation Limits X/Y/Z
This specifies the min/max rotation angles of the bone with respect to its parent.
Set Wireframe Color
Use the specified wireframe color
The display color of the object
Viewport Selecting Enabled
Object is capable of being picked in the viewport.
Script to run when the object is picked in the viewport. See select scripts .
Cache Object Transform
Caches object transforms once Houdini calculates them. This is especially useful for objects whose world space position is expensive to calculate (such as Sticky objects), and objects at the end of long parenting chains (such as Bones). This option is turned on by default for Sticky and Bone objects.
See the OBJ Caching section of the Houdini Preferences window for how to control the size of the object transform cache.