# Choose easing curves [Back to Use gameplay actions](https://rustic-game-engine.pages.dev/markdown/guides/gameplay-actions.md). `Ease.Linear` is the default. The other families are Sine, Quad, Cubic, Quart, Quint, Expo, Circ, Back, Elastic, and Bounce, each with `In`, `Out`, and `InOut` prefixes (`Ease.InOutSine`, `Ease.OutBounce`, etc.). Every time-based action uses the same core curves. Back/Elastic can overshoot numeric, vector, and quaternion progress. Path parameters, opacity, and color are bounded by their backend contracts.