Problems with Expressions


Rose’s face is proving to be a bit more trouble than I originally expected…

Some of her expressions require just a hair more know-how than I currently have, or have the patience for.  For example, I have it so her smile can be cranked up to 200% for a nice, Joker-like grin.  This requires another shape to move the nose up, but I hav no idea how this will mix with other nose shapes.  Her teeth and gums will also need to move, though I’m starting to think it’ll be better if I just don’t push her that far.


One annoying problem comes from her “mouth corner in” shapes – on their own, each of these will move the mouth to either side, along with the nose.  Combined – with the aid of a corrective shape – they form the “pucker” shape.  But when I move the sliders from 0 – 1, her nose shrinks and moves up at 0.5, only to return to normal at 1.  I tried to add another correction to compensate for this, but it only made things worse – now her nose shakes te 0.25 and 0.75.


But by far the biggest headache might be Maya’s expressions.  I’ve never used them much, and definitely not for faces – I’ve always preferrred to use utility nodes.  But I like the idea of only having a few expression nodes, rather than dozens or hundreds of utilities.  Figuring out the code to do the jobs of the utilities is a challenge, but not too difficult.  The real headache comes from Maya inexplicably mixing up my code – expressions that were working find before, and that I haven’t even touched recently, may suddenly drive the wrong shapes, or a control in an expression will be swapped out for another.  This could be a big problem, and I have no idea why it’s even happening.

The Eyes Have It

I spent most of today setting up the pose sliders for Rose’s eyes, but I’d say the results are worth it –

Yesterday I noted that it is much easier to understand how a rig works by rebuilding it. Something else I learned today, is that a character’s skin solution isn’t set in stone when you start rigging. As you’re setting up the rig, you may find it necessary to add helper joints to assist the deformation. In this case, Rose’s eye corners were sinking into her cheeks when I pull the slider down. Some extra joints help to pull the surrounding areas down, to even things out.

I’ve also added something I think the Malcolm rig was lacking: having the eyes affect the surrounding mesh as they rotate –

One other trick I’m trying out might be overkill – rather than using a wrap deformer to attach the eyebrows, I’m using a series of joints that are constrained to the surface. The main advantage to how I’ve set it up, is I can easily pull the eyebrow away from the surface for a more cartoony effect. I suppose I could have gotten the same effect by applying a cluster to the wrap-deformed brows, but I’m sure this technique may have its uses elsewhere…