Easing

Easing maps normalized leg progress to an interpolation weight. It changes how motion accelerates and decelerates while keeping the same timing. The C# library provides 31 easing functions; GDScript equivalents are planned.

Built-in functions

EaseType.Linear is the default. Each other family has In, Out, and InOut variants, for example EaseType.CubicOut.

Family	Character
`Sine`	Gentle acceleration/deceleration
`Quad`, `Cubic`, `Quart`, `Quint`	Increasingly pronounced polynomial curves
`Expo`	Strong exponential acceleration/deceleration
`Circ`	Circular curve
`Back`	Overshoots an endpoint
`Elastic`	Oscillates around an endpoint
`Bounce`	Repeated bounces

Back and elastic weights remain unclamped. Overshoot is useful for motion, but native property limits still apply to constrained values such as alpha or ranges. Try the easing selector in the gallery.

Custom functions

Supply a function from normalized progress to weight. Here sprite is an in-tree Sprite2D; import Godot and tweens.gd and run on Godot’s main thread:

var eased = sprite.TweenPosition(new Vector2(300, 120), 0.5,
    options => options.EaseFunction = t => t * t);

EaseFunction overrides Ease. A Godot Curve can also override Ease; its samples use normalized time from 0 to 1 and the curve is duplicated for each instance. Specify only one of EaseFunction and Curve; supplying both is rejected. Exceptions in easing fault playback and its completion task.