Facial Bones, Good Idea?

[EricChadwick]

Michael Comet has a great article about lipsynch. It also covers some the differences between the major methods of rigging the face.

http://www.comet-cartoons.com/toons/3ddocs/lipsync/lipsync.html

[hugo.m]

I think you can get lost with facial animation using bones. I prefere using morph targets. It takes a little longer to set up but once it's done, it's much easier and faster to animate.

Hey posm, GO RED SOX!!!:applause:

[EricChadwick]

I agree about the morph targets. Much more control. Bones are a pain to set up, especially in the lips area. But if you're exporting to games, bones is the way to go.

One of the cool ways to do it is to mix bones and morphs. The bones help with extreme mouth openings... they give you the rotation of the jaw instead of a linear morph movement (unless you're using progressive morphs). Also nice for eyelids.

Yeah, great game last night. Not normally a baseball fan, but playoffs definitely make it worth watching. Love those edge-of-the-seat finishes.

[javierdl]

What about Character Studio for lip synch?

DPC

[EricChadwick]

Hmmm. Biped is for bodies, Physique is for deformation. Do they have something new just for faces?

[javierdl]

the following text was extracted from the CS Help file, if this is not legal in any way, please tell me....

As an alternative to morphing, Physique can be used effectively for detailed facial animation when a character's face is set up with extra links. Using 3DS MAX bones or placing dummy objects at appropriate locations on the mesh head and linking them to one another, you can define a skeletal structure for moving the facial features. You can also use splines linked to the biped head to deform the mesh. You can add a spline to a character that already has Physique applied by using Add in the Physique Bones rollout and clicking the spline in the viewports.

In the example used for this topic, a snakelike character is made to talk. Dummy objects (blue cubes in the image) were linked to each other, and the parent-most was linked to the Biped head. Speech and facial expression is created by keyframing the dummy objects.

Vertex-Link assignments are determined by Physique envelopes. A single large rigid envelope on the head link insures that the whole head follows the biped. The new facial links each have deformable envelopes that add influence to specific facial features.

The 3DS MAX hierarchy does not recognize Biped's Figure mode, so special consideration is needed to establish the initial skeletal pose. Leave Figure mode on to position and link the dummy objects at frame 0; frame 0 will act as the "at rest" position for the dummies. You should start keyframing the face at frame 1 or later.

In this example the dummy in the middle of the upper lip and the dummy between the eyebrows are linked to the biped head. All the dummy objects that are positioned around the character's lips are linked in a chain to the dummy in the middle of the upper lip. The dummy objects around the character's brow are linked in a chain to the dummy between the eyebrows.

How the Dummies Should Be Linked
The dummies around the mouth are linked to create a deformation spline that follows the contours of the lips when Physique is applied. This allows smooth lip deformation when the mouth dummies are animated. The dummies on the lower eyelid create envelopes to control cheek movement, as when the character smiles, and also act as an anchor to the cheeks when the upper lip is animated. In this example, the eyebrow dummies and corresponding links control eye expression and blinking.

The snake's face is relatively simple. On the other hand, if your character has a large jaw, you may want to create links around the jawbone to separate lip motion from jaw motion. If your character has large eyes, you can add dummies and links to control eyelids separately from eyebrow motion.

The envelopes on the links between the biped head and the dummy objects are turned off at the Envelope sub-object level. Envelopes around the lips and brow are adjusted, also at the Envelope sub-object level.

Procedures

Isolate vertices of the lips from influence by inappropriate links

When working with a complicated facial bone structure, envelopes for the lower lip are bound to affect vertices in the upper lip, and vice versa. In general, this can be corrected in at the Vertex sub-object level:

Select the head and on the Modify panel turn on Vertex sub-object.

Select Initial Skeletal Pose

Click Select and fence select vertices of the lower lip, and then click Remove from Link.

Select the links of the upper lip, and click Lock Assignments.

Fence select vertices of the upper lip, and click Remove from Link.

Select links of the lower lip, and click Lock Assignments.

Keyframing the Dummies

By default, when a dummy is moved the child objects of that dummy will move also. Use the Don't Affect Children control in the Hierarchy panel, with Pivot active, if you don't want to move the child objects of the dummy you are positioning.

For example, if the dummy in the middle of the upper lip is moved, the entire mouth moves, because the child dummies inherit the move. Turn on Don't Affect Children to move this dummy independently.

Bezier position interpolation, the default 3DS MAX position controller, will sometimes overshoot a dummy key. For example, after setting a lower lip key at frame 10, you may find that at frame 13 the lip is positioned too low. Use the Bezier spline controls in the Motion panel or in Track View to correct for overshoot. For example, choose linear interpolation for the "In" and "Out" for a key.

Lip Sync

A sound track can be loaded in Track View by selecting Sound in the Track View hierarchy, selecting properties, and using the Sound Options dialog to load an audio file. Turn on Real Time in the 3DS MAX Time Configuration dialog to enable sound when you use the Play button. By scrubbing the time slider, you can locate a sound and keyframe the dummies to appropriate positions.

[EricChadwick]

Hmm, not sure what exactly you're asking.

Here's my opinion. As far as I can see, there's nothing special in CS, just some tips about how to use bones. The same conundrum exists as with a Bones/Skin setup... takes a long time editing bone influences/vert weights, as well as bone positions and # of bones.

They provide a simple cartoon-style example. Doing more realistic deformation has been easier for me with morph targets, hand-tuning each phoneme, than it has been to set up a master bone rig that works well.

Can be done though, people do it. Witness the HL2 face. But, in my experience it takes time and effort to do well. I found the lips and cheeks to be the most difficult... a lot of interplay there of many different muscles.

Another thing about bones is that it is less quick to animate... I can store some poses as sets of keys (in negative keyframes for example), but it isn't as easy to mix poses together as it is with morph targets. I end up copying a pose from the ones I saved, then tweaking it everytime, moving a lot of bones around for each pose, to give the face some variation.

Also, mixing emotion with lipsync isn't as easy in the only-bones approach.

But I haven't done a lot of facial bones animation either. Maybe someone will chime in with a more experienced approach.

[EricChadwick]

Some links I have, might be of interest.

messiah - Bones for Facial Animation
http://www.projectmessiah.com/x2/stories/story_bones_facial.htm

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

UDN - Highly Articulated Facial Skeleton for UT2k3
http://udn.epicgames.com/pub/Content/SkeletalSetup/#Highly_Articulated_Facial_Skelet

the human head - Modeling Blendshapes
http://coldfusion.art.msstate.edu/camenisch/thehumanhead/animation.html

HippyDrome - Articulating the Face
http://www.hippydrome.com/ArticulationHead.htm

[Daz]

Cheers

[Genko3D]

Really useful!

Regards,
-genko

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.