Breath¶
An autonomous breath cycle, shaped by speech and by exertion.
Breath is the quietest thing FaceCue does and one of the most effective. A character who is not breathing reads as a prop, and almost nobody watching can say why.
The Cycle¶
A resting rhythm that runs on its own, all the time, whether or not anything else is happening.
Breath does not start with a line and fade out after it. It is always running, and speech shapes it. So a character standing silently is still breathing, and moving into and out of a line changes a rhythm that was already there.
While Speaking¶
Speech rides on the exhale. You cannot talk while breathing in, and the face shows it.
The breath holds low through a line, because the speaker is spending an exhale on it instead of cycling normally. A pause draws a refill, the breath a speaker takes when they have run out and have more to say.
That pattern is most of why breath is worth having on a talking character. A line delivered by someone who never seems to run out of air reads as synthetic, and the refill in the gap is the thing that fixes it.
FaceCue places that refill from the line as it plays. The bake already marks where the speaker actually drew breath, and taking each breath there is on the roadmap.
Exertion¶
Effort deepens and quickens the cycle, and the character settles afterwards instead of snapping back.
The settling is the part worth tuning. Someone who has just stopped running does not return to a resting rhythm immediately, and the recovery is more visible than the exertion itself.
What It Moves¶
The body, and the belly most of all. At rest the belly swells forward on each breath in, the shoulders rise and fall a moment behind it, and the head floats with a small nod in time, so a resting character never locks in place. As the character works harder, the chest joins in and the shoulders lift much further.
Each of those is its own section on the Breath driver, and each can be switched off.
Breath is deliberately easy to scope down. On a character seen from the shoulders up, the shoulders and the head carry it, and everything below them is wasted.
The bones each part moves are generally picked for you. Every character is built a little differently, though, and one whose proportions are far from average may breathe a little differently than you expect, so they are worth checking on your own rig. Watch a few breaths, and check which bones each part found on the Breath driver's Setup. Where the chest ends and the lower back begins is set on the Eyes driver, under Auto-Setup.
Belly & Chest¶
The belly and the chest each need at least two bones to move: two in the lower back for the belly, and two in the chest for the chest. Most rigs carry only one bone in the lower back, so on those the OneClick Wizard sets up the chest and leaves the belly off. MetaHuman and Daz characters have both.
Whether that is enough is your call, and it depends on the character and on how close the camera comes. Watch a few breaths. If the chest does not sit right on its own, switch it off too and let the shoulders carry the breath, or turn the breath off altogether.
For higher fidelity, give the belly and the chest a blendshape of their own, a swell sculpted for the purpose. Each can run on it instead of its bones, or alongside them. None of the supported rig families include one among their standard shapes, so it is something to add to the character yourself.
The most fidelity of all would come from breathing that reaches the face, the nostrils and the mouth. It takes care to get right, and we are eager to bring it to you when it is ready. It is on the roadmap.
The Blendshape Pick Is a Stopgap
For now the swell's blendshape is chosen on the Breath driver itself, as a Morph Renderer and a Morph Shape for each part. That is temporary. When breathing reaches the face, breath gets its own channel in the Face Rig Designer and its own rig map, the way speech and emotion have theirs, and this choice moves there with it.
Tuning It¶
Three things, in the order they are worth touching.
Depth. How much movement a breath produces, set on each part: the belly's Peak Swell (°) and the shoulders' Peak Elevation (°). The most common mistake is too much. Real breathing at rest is barely visible, and a body that heaves reads as distress.
Rate. How fast the cycle runs, as Idle Rate (bpm) and Listening Rate (bpm) under Per-State Settings. Slower reads as calm, faster as agitated, and it is an effective character trait on its own.
How much speech slows it. Hold Rate Scale, on the While Talking tab: how far the cycle eases down through a line, since speech is mostly one long exhale.