Key Concept: Pole Vectors

• PV really is “twistâ€?applied to IK chains

  • Establishes a frame of reference for IK twist
  • Can use either PV or twist parameter

• Same limitations as aim constraints

  • Another case of gimbal lock
  • Which way is up?
  • Reference frame isn't consistent!

• Beware the Jiggler of Doom!

  • Flips happen as effector nears the PV
    • the Vector, not the handle
    • The vector goes both ways!
  • Only fix: move PV out of way