# Animation Curve Overview

The animation curve, defined by a timing function, is a speed curve that controls the time consumed by an animation on attribute changes. The slope of the animation curve at a certain moment indicates the animation velocity and corresponds to the attribute change speed. A well-designed animation curve should be continuously smooth, in line with the user's intent, and consistent with the real world. When designing animation curves for your animations and transitions, take into account use cases and user intents.

Animation curves can be classified into physics-based curves (ArkUI provides multiple physics-based spring curves) and traditional curves based on whether they model the real world. Compared with the traditional curve, the movement trajectory generated by the physics-based curve would feel more natural to users and help create a more engaging experience. In light of this, you are advised to use the physics-based curve when possible.