# Evaluate interpolation [Back to Use gameplay actions](https://rustic-game-engine.pages.dev/markdown/guides/gameplay-actions.md). `Smooth.lerp` and `slerp` accept shared easing. `inverseLerp` and `remap` do not clamp values. `smoothDamp(current, target, velocity, smoothTime, delta)` returns updated value and velocity; pass the velocity into the next call. It uses an analytic damped spring rather than a frame-rate-dependent fixed fraction. `Interpolation` exposes the same math. Smoothing is synchronous; actions and callbacks are asynchronous.