Facial animation in Max...

Fordy

Hi All

I have just bought the Discreet Production Workflow DVD's (for Character studio 4).

On the Dvd's it shows a model's face being animated using bones attached to the biped. What it doesnt seem to mention is anything about making the character blink.

I was wondering how you pro's make your characters blink using a biped/bone setup ?

Regards,

Rick Stirling

Does it tell you how to link the bones etc? I'm assuming it does (if not, the quick answer is position the bones and use select and link to the parent bone).

I've done a lot of face boning and rigging, especially recently. I use a bone for each eyelid, with the bone root in the center on the eyeball and the end of the bone at the edge of the lid.

You need to have enough polygones for the eyeball, depending on how far you set it into the head and the polycount you will often find that one row is enough.


Then I weight the eylid to the bone.

Eric Chadwick

FWIW, we do it the same way here.

JonMurphy

Time to break out the head-rig pic again



As Rick says, the keys to good eyelid bones is getting the pivot in the right place, and having the polys in the lid so that it rolls over the eyeball well.

Snowfly

Great info here..

If you wanted to take the blendshape route, would you have to detach the head, or "paint" the geometry somehow so only certain verts in the head are included in the morph?

Fordy

Hi Rick: Yep, it does tell you how to link the bones, but it doesnt actually seem to use moving eyes and eyelids, It basically relies upon just scrunching the face up a bit to suggest general emotions.

Hi Jon: Thanks for the picture, that give me a good idea as to where to put the bones in the face, not that i'll need it just yet as the main function of the DVD's is the characters movement. I'll certainly save the picture though, it's gonna come in useful!

Just a couple of querys though: Obviously a blink is pretty quick, I guess a blink is animated in 2 frames? 1st frame, eyelid down, 2nd frame back up? I reckon it would look pretty quick in realtime when its rendered?

Also, do you have to animate every set of blinks, isn't it possible to generate them randomly at fairly regular intervals? (I suspect it wold prolly involve scripting and if so it doesnt matter, I dont want to mess in that side of things)

Thanks all!

thomasp

what about using dummies instead of bones? this way you're not restricted to animating rotations, but are able to freely deform the skinned mesh by shifting the controls around.
worked for me on a few occassions.

Eric Chadwick

[ QUOTE ]
If you wanted to take the blendshape route, would you have to detach the head, or "paint" the geometry somehow so only certain verts in the head are included in the morph?

[/ QUOTE ] Depends on the engine if you're going out to a game. But if just for rendering in Max, there are a couple ways to do it.

If you use Morpher, you can detach the head at the neckline. Then create your morph shapes from it. Then add modifiers to it like this:

Skin (assign face to a single bone, animate body)
Edit Poly (attach body, weld neck)
Morpher (animate facial morphs here)
Editable Poly (base head pose)

You can also assign bones to the eyelids at this point, instead of using morphs. Or you can use progressive morphing to get "rotation" of the lids.

Fordy, about the blinks... I've seen people script in blinks to happen fairly randomly, either with wiring, or with a carefully-tuned Noise controller, or just copying the blink keyframes to whenever they want them. If for in-game use, the bone rotations can be assigned to a behavior, or if you're just doing an in-game cutscene then you can just keyframe it.

Something interesting: blinks also coincide with turning the head... ever try to keep your eyes open when you whip your head around to look out the window? Eyes seem to need a rest during fast head movements... so you'll probably want to keyframe some of those blinks.

A couple related threads...

creating eyelashes that move with morph-targeted eyelid animation?
http://www.cgtalk.com/showthread.php?s=&threadid=8287

Animating polygon eyelashes?
http://www.cgtalk.com/showthread.php?s=&threadid=58270

Rick Stirling

When you turn your head the eyes dont stay static, they flutter around in increments of I beleive 7 degrees. Or maybe 3.

What you will probably end up doing in an engine is keyframing several poses, then blending between them. I can't discuss the last stuff I did, but in spooks we had a base/rest pose, 13 phenomes, 7 visemes and a blink.

A good engine/coder will blend these, so you can speak and blend in smiles/frowns/emotions over the top.

Fordy

Thank you all for replying, especially Rick, for having taken the time to explain things in detail!

Regards,