Animator Coexistence¶
What happens when FaceCue and your animation want the same character. What you should expect to see, what FaceCue promises, and the few things you can tune.
The short version: your animation keeps playing, and FaceCue's ambient motion rides on top of it. A breath, a nod or the head's idle sway is added to whatever the animation is doing, never written over it. A look is the one exception. While the character is looking at something, the look takes over the bones the gaze turns and only those, the rest of your animation keeps going, and the ambient motion carries on over both. When FaceCue is done with a bone, it gives it back.
None of this needs setting up. It is how the character behaves the moment the wizard is finished.
Where FaceCue Sits¶
FaceCue works with your animation, not against it, and one rule says how: ambient motion adds, a look takes over.
Ambient Motion Adds¶
Breathing, nods, the head's idle sway and the other small motion that keeps a character alive start from whatever the animator posed and ride on top of it, fresh every frame. So an animation that is moving a bone goes on moving it underneath whatever FaceCue is adding, and the moment your animation poses a bone, FaceCue carries on from that pose.
A Look Takes Over¶
A look has to land on what the character is looking at, so while it lasts it takes over the bones the gaze turns, and only those: the eyes, the head and the neck, and the body too whenever the look leans or turns it. The rest of your animation keeps going, and the look stays on its target while the body moves underneath it. When the look ends, those bones ease back onto your animation.
The ambient motion carries on over both. The breath and the nods ride on the look just as they ride on the animation, and the idle sway keeps going at a gentler strength while the character looks.
Bones: Holding & Handing Back¶
FaceCue moves bones for a look, for breathing, and for the small motion of the head and the body. On a character that is also playing an animation, this is what you will see.
- Your animation never stops. A head the animation is turning keeps turning, with the breath and the idle motion added on top. While a look lasts, the look holds the head on its target instead, and the head picks the animation back up when the look ends. Every bone the look does not turn stays with your animation throughout.
- While a look lasts, the head holds steady. There is no flicker between the animation's pose and FaceCue's, even on animations that only update the head every few frames.
- When the look ends, the head eases back. It settles into whatever the animation is doing over a fraction of a second. It does not snap there.
- A momentary glance away does not cause a back-and-forth. If the character's attention drops for an instant and returns, the head stays where it is instead of releasing and grabbing again.
- Nothing gets stuck. If whatever was moving a bone is interrupted, the bone goes back to the animation on its own. A paused or frozen character keeps its pose until it is running again.
- Turning a driver off is immediate. Disable the Eyes driver and the head is back on the animation at once.
What This Looks Like
An animation turns the head to the left. Partway through, the character is told to look at something on the right.
The look takes the head to the target and keeps it there, while the rest of the body goes on with the animation. The breath and the idle sway carry on over both the whole time. When the look ends, the head eases back onto the animation over a fraction of a second and continues from wherever the animation has got to.
Smoothing the Animation Underneath¶
Animation often reaches a bone in small steps, and anything FaceCue adds on top of a stepping pose would step with it.
So FaceCue smooths the pose it builds on. The result glides where the animation stepped, and FaceCue's motion rides on the glide.
Smoothing has to know when not to. A teleport, a camera cut or a genuinely fast animation must land instantly, not smear across the smoothing window, so any jump in the animation beyond a threshold passes straight through unsmoothed.
Blendshapes¶
Bones are shared. Blendshapes, in practice, are not, and the rule for them is simpler.
FaceCue writes the blendshapes it is driving, after the animator, with its own values. A blendshape FaceCue is not driving is never touched. When a driver stops using a blendshape it puts it back to rest once and then leaves it alone.
What that means for an animation that keys a facial blendshape FaceCue also drives: on the frames FaceCue has something to say about it, FaceCue's value is what shows. FaceCue does not read what the animation set and add to it. A script or plugin of your own that sets blendshapes can share them with FaceCue instead, as Writing a Blendshape describes.
So if your animation carries part of the face, say the brows, the clean answer is to stop FaceCue driving that part. The Emphasis driver's Brow switch is there for exactly this, and a driver can be kept off a whole mesh through its Renderer Groups.
Animated Eyes¶
Eyes get one extra rule of their own, because they are the one place where an animation and the character's own attention can want different things at the same moment.
The rule sits with the rest of the animation settings, on the brain under Animator Coexistence, in its Animated Eyes section. It shows once the character has an Eyes driver, and it comes down to one choice, When Animated:
- Step Aside, the default, hands the eyes over while an animation is moving them, and picks the character's own gaze back up once it stops. An authored glance plays as authored. Keep Small Movements, alongside it, keeps the tiny darts and drift riding on top of the animated pose so the eyes still look alive during the glance.
- Keep Looking keeps the character's own gaze running whatever the animation does. It is what you want if the eyes are animated but you would still rather have the character looking where it decides to look.
An animation only takes the eyes when it actually moves them, so one that happens to hold the eye bones still does not.
A character that drives its eyes through look blendshapes has nothing to step aside for, because its eye bones carry FaceCue's own gaze and no animation's. The section says so in place.
The rest of what the Eyes driver does while at rest, the small movements that can keep running on top of an animated glance, is on Eyes & Gaze.
IK Compensation: Hands That Stay Where You Put Them¶
A look that turns the body turns the arm with it, and the arm drags a placed hand off its mark.
FaceCue can undo that. It puts each hand back where the animation had it, and undoes only its own drag. Your animation, root motion and any other IK on the arm are left exactly as they were.
It is off by default and lives on the FaceCue Resolver. Each hand carries its own weight for how firmly it is held, starting at none, and a hand you would rather leave to another system, such as Animation Rigging, can be excluded on its own. It is still early, so check it on your own rig first. Setting it up, and holding a hand from a script only while it needs holding, is on The Resolver.
Freezing & Thawing¶
A face that freezes, because nobody can see it or because you froze it, stops everything FaceCue contributes. Nothing is simulated and nothing is written, so the character costs essentially nothing. What it does not do is snap.
Over a short blend it fades onto the body's own pose while it keeps running, then stops altogether. From then on your animation, and anything else, has the character to itself. On the way back it fades in again from wherever the body left the head, so a body the animator kept moving while the face was frozen is picked up, not snapped to.
How long the blend takes is Freeze Blend, on the clock page: One Clock. What triggers a freeze, visibility and distance, is set out there too.
If your animator's culling mode is set to always animate, FaceCue's visibility check can be pointed at the animator and the face keeps going too. That is set in the brain's Optimization section, covered in Optimization.
Nothing to Set for Update Modes¶
An animator set to update on the physics step runs at a different rate from the display. FaceCue allows for that on its own, so there is nothing to change on your side. Set the animator up the way your project needs and the face follows.
Physics sees the character as it was last drawn, FaceCue's movement included, whatever the Solve Schedule says. A collider on the head follows the head FaceCue turned. One case differs: an animator set to update on the physics step poses the bones after each physics step, so in a frame that runs more than one physics step, the later steps see the animation without FaceCue's movement.
What You Can Tune¶
Everything above is on by default and works without a visit. When a character needs adjusting, the controls live in one place on the brain, under Animator Coexistence, in this order.
| Control | What it changes |
|---|---|
| Assert Bone Ownership | The hold itself. Leave it on. It exists to be switched off only to compare against the raw per-frame behaviour |
| Ownership | |
| Handback Time | How long a released bone takes to glide back to the animation. Shorter feels more responsive, longer hides sparse animation steps during the return |
| Release Debounce (s) | How long a look waits after engagement drops before letting go. It belongs to the Eyes driver and is mirrored here |
| Smoothing | |
| Base Smoothing | Smoothing of the animation pose FaceCue builds on. Leave it on |
| Smoothing Response | How tightly the smoothing follows the animation. Shorter follows fast motion more closely, longer smooths harder but lags |
| Snap Threshold | How big a jump in the animation passes through unsmoothed, in degrees |
| Animated Eyes | |
| When Animated | Whether the eyes step aside for an animation moving them or keep looking. See Animated Eyes |
| Keep Small Movements | Whether the tiny darts and drift keep riding on an animated glance, under Step Aside |
Animated Eyes stays in place when Assert Bone Ownership is off, since stepping aside for an animation does not depend on the hold.
The freeze blend is on the brain under Facial Timestep, in its Clock Rate section, as Freeze Blend (ms). It is covered with the rates on One Clock.
Start From the Symptom
Most characters never need any of this. If one does, the symptom says where to look.
A head that flickers while looking is a hold that has been switched off. A look that ends with a jump wants a longer Handback Time. A base that steps under held motion wants Base Smoothing, and one that smears through a camera cut wants a lower Snap Threshold. An authored glance the character keeps overriding wants Step Aside.