Sibling of L3 Tween.

Install

Add as a git package:

https://github.com/Less3Design/L3-spring.git

Usage

private Spring3 moveSpring;

void Start()
{
    moveSpring = Spring3.At(transform.position)
        .SetOnUpdate(p => transform.position = p)
        .SetOnComplete(() => Debug.Log("arrived"));
}

void MoveTo(Vector3 point) => moveSpring = moveSpring.SetTarget(point);

• Spring, Spring2, Spring3, Spring4 spring a float, Vector2, Vector3, Vector4.
• Handles are readonly structs. Always assign the result of every call.
• SetTarget on a moving spring changes its goal and keeps its momentum. On an idle spring it starts a new one from where the last stopped, with the same settings.
• A spring is done when it is within restThreshold of the target and nearly stopped. It snaps to the target, calls onUpdate once more, then onComplete.
• Idle springs hold no pool slot. Nothing to clean up.

Tuning

acceleration = -stiffness * (value - target) - damping * velocity

SetFrequency(hz, ratio) is the easy way to set both:

• hz: how fast. Oscillations per second if there were no damping.
• ratio: how bouncy. 0 bounces forever, 1 no overshoot, >1 sluggish.

Default is 170 stiffness, 26 damping (ratio 1).

restThreshold defaults to 0.001, which suits 0..1 values. Raise it for world units.

Pool

256 springs, doubles as needed up to 4096. Change it in Project Settings > Less3 > Spring, or in code before the first spring:

[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
static void ConfigureSprings() => SpringManager.Configure(initialPoolSize: 512, maxPoolSize: 8192);