Bone Constraints

Bone Constraints (Available in Pose mode and Edit mode)

The Avastar Rig tries to keep most of its complexity under the covers. The most important and unfrtunately also the least understood part of the rig is its control bone section together with its set of Bone constraints. Here is a bit of information to shed some light on this.

The (green) Control Bones and the (blue) SL Base Bones of the Avastar rig are closely related to each other. Actually the SL Base Bones by default inherit the control Bones Transformation matrices. Hence the control bone skeleton and the SL Base bone skeleton are like almost perfectly synchronized twins. You can see this best with Bone display mode set to Octahedral:


The Green Control Bones are the master bones used for Animation


The SL Base Bones are used for Skinning (Weighting). They follow the green control bones

Due to the Bone constraints the SL Base bones can normally not be directly moved or rotated. Hence by default you have to move the control bones and weight the SL Base bones.

However there are 2 situations where you want to change the default behavior:

  • When you Skin your Mesh (When you do weight painting tasks) then you almost always want to unlock the Bone Rotations of the Blue SL Base Bones. Then you are free to pose the Deform bones for testing purposes.
  • When you Animate your Character, then you may want to unlock the Location Constraints of the Green Control bones, so that you can also perform Location animations.
Hint: Although the Locking of Rotations and the Locking of Locations seems to be related, they actually are not. The unlocking is used to handle 2 completely different situations! It is important to get this sorted out and understand the difference as explained briefly above!

Bone Constraints Panel (in Edit/Pose Mode)

  • Bone Constraints Selector: Here you can specify if you want to affect
    • All Pose Bones
    • All Visible Pose Bones
    • All Selected Pose Bones
  • SL Bone Rot: Lock/Unlock the rotation of the SL Base Bones (good for weighting tasks)
  • Control Bone Loc: Lock/Unlock the Location of the Control Bones (good for special animations i.e. face animation)

Note: The Bone Workflow Presets (see further above) take this into account. So when you select the Skin preset, then the constraints are automatically set appropriate for the Weighting