Keyframe interpolation is the method by which software calculates the intermediate values between two keyframes, determining how a property transitions from one state to another.
When an animator sets a keyframe at frame 1 with a position of 0 and another at frame 30 with a position of 100, the software must determine the value at every frame in between. This calculation process is called interpolation. The type of interpolation chosen dramatically affects the result: linear interpolation creates constant-speed movement, while bezier interpolation allows for smooth acceleration and deceleration curves.
Most professional animation tools offer several interpolation types. Linear interpolation moves at a constant rate and is useful for mechanical movements. Bezier (or smooth) interpolation uses adjustable curves for natural-feeling motion. Hold interpolation maintains a value unchanged until the next keyframe, creating abrupt switches — useful for visibility toggles or step-based animations.
Spatial interpolation also matters when animating position. A linear spatial path moves an element in a straight line between keyframes, while a bezier spatial path creates curved motion paths. Understanding interpolation options helps in communicating with animators about the specific quality of movement desired, whether that is a smooth arc, a sharp linear path, or a bouncing elastic effect.
A bezier curve is a mathematical curve defined by control points, used in animation to create custom easing and motion paths with precise control over acceleration and direction.
Easing refers to the acceleration and deceleration curves applied to animations, making movements feel natural rather than mechanical and linear.
A keyframe is a specific point on a timeline that marks the beginning or end of a change in a property such as position, scale, opacity, or rotation.