Post 41 - Parenting considerations and work around

After working with phonemes (shapes used in speech which can be difficult to animate) I came across a reaction manager / rotation problem. The jaw is already wired to the jaw controller and so cannot be given additional driven keys. However, there is a way around this. I have created several morph targets for some phonemes, but both the 'A' and 'O' need a slight jaw movement. Setting a state and slave would be the way to do this, but we need to move / influence the jaw bone without interfering with the jaw control reaction. I ended up using the rotation of the point helper, which is parented to the top of the jaw (as used earlier to zero out the transformation information). As this is connected to the jaw, it moves the jaw when it is rotated, so this was used for the 'A' phoneme. Next is the 'O' shape. the jaw bone has a 'cap', or 'nub' bone at the end of it which sticks out of the chin. As it was a small amount of influence I needed, this one was connected using it's position rather than rotation.


This work around has paid off and is an industry standard way of working. This is one of the main rules of rigging, which is to try and avoid parenting or having direct connections with the geometry and use parented point helpers instead. This technique is true for the full figure model also in the arms, legs, back, eyes and muscle bones.

You will notice in the video that the jaw has been animated to open twice. What can be seen is that the first 'jaw open' is driving the jaw as the point helper doe not move, but the second 'jaw open' is the 'O' phoneme and so is being driven by the point helper (seen by it rotating, casusing the jaw to rotate also).










Jaw parenting clip - LINK