Weta FACS - notes and observations

Notes and observations on the Weta FACS action unit list.

Each AU (action unit) is followed by notes on splits (L/R, upper/lower), if the attribute is absolute (ie 0 to 1) or positive/negative (ie -1 to 0 to +1) (noted as P/N), and if it corresponds to a "standard" AU.

I've made some assumptions, such as the tongue AUs being P/N, and that the lip shapes are actually split upper/lower rather than each being it's own sculpt (except for obvious cases like upper lip raiser).

AU's in italics are ones that are not listed on the deep learning slide, and I think are safe to assume are secondary shapes for detailing.

I count roughly 95 sculpted "core" shapes, not including splits or combos.

Roughly 18 tongue AUs.

Naming convention

upper/lower splits are always defined as a prefix, L/R splits are always defined as a suffix, they also use camelCase according to the deep learning slide.

eg.

    upperLipFunnelerL

    upperLipFunnelerR

    lowerLipFunnelerL

    lowerLipFunnelerR

Brows

They have a few shapes for popping out veins on the forehead...

supra orbital vein  L/R

This one is going up the forehead from the eyes.

supratrochlear vein

The supratrochlear is the one going up the forehead from either side of the nose bride.

temporal vein  L/R

The temporal artery is often seen when someone is straining or angry.

(yes I just used a meme as reference, deal with it)

Nose

nasojugal groove  L/R

This is one that you don't often see, it's the line at the top of the cheek where it meets the skin under the lower eyelid, the crease is formed where the thick nasolabial fatty pad meets the thin infraorbital skin.

The groove continues around the eye into the palpebromalar groove, together they form the infraorbital margin.

I'd assume this shape deepens the groove?

(The orange line in the image above.)

Anatomy for sculptors - smile reference

https://www.artstation.com/anatomy4sculptors

Lip Corners

dimpler  L/R  AU14

marionette dimpler  L/R

Melinda Ozel made some interesting notes on the variations on the dimpler AU, and how it's too complex to represent as a single action unit, I would assume the "marionette dimpler" is Weta's interpretation of one of these variations.

https://melindaozel.com/facs-cheat-sheet/

https://melindaozel.com/zygomaticus-major-variations-the-dimple/

lip vermilion line tweak  L/R  upper/lower

lip vermilion line soften  L/R  upper/lower

This is a cool one that I can see being useful, the vermilion line is the sharp border around the edge of the lips, so being able to accent or soften this could really help to define an expression

https://en.wikipedia.org/wiki/Vermilion_border

Also, learned a couple of new terms there, "philtral columns" and "oral commissures"!