2+1 FK Torso

• What:

  • 2-DOF FK joints from pelvis to torso
  • 1-axis fixup parented to each spine link to handle twist
    • Shown here offset; actually co-located
  • Torso's twist rotation drives fixups
  • Skin is bound to fixups

• For:

  • Animate spine links with 2-axis FK
  • Animate twist rotation on top chest joint
    • Twist rotation distributed across fixups by expression or drivers
    • Fixups never hand-animated

• Pros & Cons:

  • Like FK but more predictable
  • Twist response can be tweaked in expression