Shapes and Phonemes
The decision of which shapes to build came from two primary sources. First, Rick Grandy, the technical editor for this book, came up with a preliminary list, and then the animator, Kyle Clark, came up with some items that he needed to get this project done. Overall there were 66 targets built for this animation, and there will probably be some more that need to be built as more animation is done. Some models used for production have more than 200 blend shapes modeled. The face shapes were broken down by region:
Phonemes are face shapes directly related to speech. Different theories exist as to which phonemes are required for animation of speech. Thirteen accepted shapes are recognized as vismemes, which are used in the creation of English speech. These shapes are as follows:
- Eyebrows, left, center and right. The shapes created for this region allowed the eyebrows to animate up and down, slide inward toward the center or out away from the center, and bow in the middle upward and downward. Shapes for the brow animate the eyebrows into even smaller regions: the left, right and center for the left brow, and the left, right and center for the right brow.
- Eyelids, left and right. The shapes made for the eyelids allowed for the eye to close, by pulling the upper lid down, and allowed the eye to squint, by pulling the upper and lower lids to meet in the center.
- Face (for broad shapes), left and right. The face groups had shapes that animated the cheeks up and down, moved the cheeks in and out, and puffed the cheeks out and sucked them in. There was also some cheek deformation on broad mouth shapes, such as the dread, sneer, smirk and grin.
- Mouth (the largest group), left, center and right. These shapes created simple as well as complex mouth movement. The simple movement includes moving the each lip up, down, curl in, curl out, corner up, corner down, corner side movement inward, corner side movement outward and shapes that smoothed out the corners of the mouth.
The complex shapes required the modeling of the frown, smile, furrowing, puckering, pouting, yawning and kissing.
- Overall face shapes, localized by region. These shapes simply used large areas of the face to accomplish a single task. This kind of approach is preferable when there is a specific target that the animator may want to hit with a single blend shape.
These shapes include mouth smirk, mouth sneer, mouth dread, mouth wince, eye furrow, eye squint and mouth smile.
The mouth regions were extended to include the cheeks, and the eye regions were extended to include the forehead and eyebrows.
- Closed mouth: P in pie, B in book, M in mother.
- Pursed lips: W in wicked, OO in root.
- Rounded lips, corners of the mouth slightly puckered: R at the beginning of a word, OO in book.
- Lower lip drawn to upper teeth: V in victory, F in French.
- Tongue between teeth with gaps on the side of the tongue: TH in think.
- Tongue behind teeth with gaps on each side of tongue: L in look.
- Relaxed mouth, mostly closed teeth, tongue visible behind the teeth: D in dog, T in tag, Z in zebra, S in sit, R in car, N in nothing.
- Slightly open mouth, mostly closed teeth, corners of the lips slightly tightened: CHI in chime, JI in jive, SH in shy, VI in vision.
- Slightly open mouth, mostly closed teeth: Y yawn, G in get, K in kitchen.
- Wide mouth, slightly open lips: EA in meat, I in rip.
- Neutral mouth, teeth slightly parted, jaw dropped slightly: E in bet, U in but, AI in bait.
- Round lips, jaw dropped slightly: OA in toad, O in rope.
- Open mouth, jaw dropped: A in math, O in shop.
For the list of shapes that would be modeled for this model, the phonemes were reduced to eight basic shapes:
- Wide, slightly open lips: E in evening.
- Round lips, jaw slightly open: O in oh, O in toast.
- Round lips, corners of the mouth puckered: OO in book.
- Closed mouth: P in pie, B in book.
- Lower lip drawn to upper teeth: F in fine, V in vase.
- Lips pursed: W in work.
- Mouth open, tongue visible from inside mouth: T in tank, D in dog.
- Relaxed mouth, mostly closed teeth, tongue visible behind the teeth: S in sit.