I can see you're interested in learning more about the rigging process for that interesting facial orientation setup! This is a really clever technique for creating faces that can turn in different directions.
Understanding the Setup
This rig creates a 2.5D depth effect that allows a face to appear to turn while maintaining a flat, illustrative style. Here's how it works in more detail:
The Core Concept
The technique uses transform constraints to create opposing bone movements. Here's the breakdown:
Three main bones : You need a parent bone (like head), a control bone (control), and a target bone (control-back)
Transform constraint setup : The control-back bone uses a transform constraint that follows the control bone with a translation mix set to -100% . This makes it move in the exact opposite direction of the control bone.
Mesh weighting : The facial mesh is weighted to all three bones:
The center/middle vertices are weighted to the control bone
The outer edge vertices are weighted to the control-back bone
The base weight goes to the parent head bone The Painting Process
When weighting the mesh:
Start with all vertices at 100% influence from the head bone (neutral state)
Use weight painting in additive mode to paint the middle vertices to be influenced by control
Paint the outer edge vertices to be influenced by control-back
This creates concentric rings of influence that simulate a spherical surface For a detailed video tutorial showing the complete rigging process for both round and angular versions of this technique, check out this stream: VIDEO
You can also download example projects to study the setup directly from http://esotericsoftware.com/spine-twitch.php
