> For the complete documentation index, see [llms.txt](https://postica.gitbook.io/binding-system-3/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://postica.gitbook.io/binding-system-3/pipeline/tweening.md). # Tweening and Control Easing and damping, inside the binding. A bound value normally follows its source exactly. These modifiers put time between the two: the value moves *toward* the source rather than snapping to it. That turns a binding into an animation with no animator, no coroutine and no tween library. {% hint style="success" %} **Learn by doing:** [Making a Value Follow Smoothly](/binding-system-3/tutorials/smooth-values.md) puts a Tween Animation and a Value Smoother on the same jumping value, side by side. {% endhint %}

Modifier	What it does
Tween Animation	Eases toward the target over a duration, with an easing function.
Value Smoother	Follows the target continuously with damped dynamics. No duration, no overshoot.
Blend To	Blends toward a target value by a factor.

Available for `float`, `Vector2`, `Vector3`, `Color` and `Quaternion`, depending on the modifier. {% hint style="warning" %} All of these only advance when the binding runs. On a [proxy binding](/binding-system-3/overview/proxy-bindings.md) that means an update point has to be selected, exactly as for any other binding: adding a tween modifier does not select one for you. On a `Bind` field it means your own code has to keep reading the value, or **Auto Update** has to be on. There is no point easing a value that is only read once. {% endhint %} ## Tween Animation The one to use when you know how long the movement should take.

Setting	What it does
Function	Linear, Sine, Quad, Cubic, Quart, Quint, Expo, Circ, Back, Bounce, Elastic, or a custom `AnimationCurve`.
Ease type	Ease In, Ease Out, Ease In Out.
Duration and Delay	In seconds. Both bindable.
Direction	Forward, Backward, PingPong, ReversePingPong.
Repeat count	How many times. Zero means forever.
Time scale	Scaled follows `Time.timeScale`; Unscaled ignores it, which is what a pause menu wants.
Origin type	Where the tween starts from: a precise origin you supply, or the last completed value.
On target change	What happens when the target moves mid-tween: Ignore, Restart Animation Time, Restart From Origin, or Adapt Animation.
Events	`UnityEvent`s for started, updated and completed.

**On target change** is the setting worth understanding, because a bound target usually *does* move mid-tween.

Behaviour	What it does
Ignore	Finish the current tween, then start a new one. Predictable timing, can lag behind a fast-moving target.
Restart Animation Time	Keep the current position, restart the clock toward the new target.
Restart Animation From Origin	Jump back to the origin and tween again. Rarely what you want for a continuous value.
Adapt Animation (Unsafe)	Retarget without restarting. Smoothest, and labelled unsafe because the easing shape is no longer exactly the curve you chose.

## Value Smoother The one to use when there is no fixed duration, only "follow this, but smoothly". Damped dynamics, so it converges without overshooting, and it handles a target that changes every frame without any special case.

Setting	What it does
Speed	How fast the value follows the target. Higher is snappier. Range 0.5 to 25, default 8. Bindable.
Damping	How smoothly it stops. 1 is critical damping, meaning no overshoot; below 1 overshoots, above 1 is sluggish. Range 0 to 5, default 1. Bindable.
Delay	Before the chase starts. Bindable.
Time scale	Scaled or unscaled.
Origin type	Precise origin, or last completed value.
On target reached	Stay at the target, or reset to the origin.
Target epsilon	How close counts as arrived. Default 0.001.

This is the right default for camera follow, UI values that jitter, and anything driven by physics or input. ## The easing picker The ease button on a **Tween Animation** modifier opens a grid that plots every easing function, so you pick by shape rather than by name. **Custom** takes an `AnimationCurve` instead.

The easing picker, opened from the Tween Animation modifier

## Choosing

You want	Use this
A UI element to animate in over 0.3 seconds	Tween Animation, Ease Out
A health bar to catch up to a value that keeps changing	Value Smoother
A camera to follow a target without jitter	Value Smoother
A number to count up to its new value	Tween Animation, Linear
A value to lag behind by a fixed time	Value Delayer

## Cost These modifiers are the ones that genuinely run every frame, since that is the point of them. Two things keep the cost down: * Pick the cheapest [update point](/binding-system-3/overview/modes-and-updates.md) that looks right. **LATE UPDATE** for anything visual. * Do **not** put them on an [interval](/binding-system-3/overview/modes-and-updates.md#intervals). An animation stepped every four frames is an animation with four times fewer frames, and it looks it. The interval is the one update setting that genuinely breaks them. {% hint style="success" %} **Optimized Update is safe with these, and you can leave it on.** A modifier that has work to do between source changes declares itself dynamic, and the pipeline splits in two around it: the part before it is cached against the raw source value, and the part from it onward is re-evaluated on every update. The change check then reports new data every time, so the tween keeps advancing while the cheap half stays cached. This is handled for you; there is nothing to configure. {% endhint %}