Lightwave Notes on Rigging

What, no Up-Vector?

Anyone who has tried their hand on rigging a character with bones has had to deal with out of control IK-chains that want to bend in any direction except the one desired. Most software packages offer an "Up-Vector" as a helping hand. This is often a NULL object, the position of which determines the general direction of the bending chain. This is especially helpful for arms and legs.

To my dismay I could find no mention of such a vector in any of the Bone property or motion windows, nor is it mentioned anywhere in the documentation. Still, there is a way to use a NULL object as an Up Vector in LightWave. Here is how:

Say you have a leg consisting of three bones: Upper, Lower and Foot. We use a NULL object as Goal. We create another NULL, call it UpVector and place in a little in front of the knee

Unfortunately this setup only works for the first bone in a chain. So if this leg is attached (parented) to a hip bone, it no longer works as desired... Look for a better solution I must!

Motion Panel Settings

For the Foot bone we choose Goal as the goal, and turn on Real Time IK
For the Lower bone we turn on Inverse Kinematics only on the Pitch Controller
For the Upper bone we choose UpVector as the Target Item. This automatically turns on Point at Target for both the Heading and the Pitch Controller. Turn on Inverse Kinematics on the Pitch and the Bank Controller, leaving Point at Target only on the Heading Controller

And it all should work!

Here's a Lightwave Scene (and Object) where this is all set up

More notes on rigging can be found here

← BACK

↑ LW Index

↑ 3D Index