Easing is the difference between motion and movement

Linear motion — constant speed from A to B — does not exist in the physical world, so our eyes read it as mechanical. Easing describes how a value accelerates and decelerates between two keyframes, and choosing it well is the single cheapest upgrade available to a mockup animation.

Ease out for arrivals, ease in-out for journeys

A camera that starts fast and settles gently — ease out — feels confident and is the right default for a push toward a device. Symmetrical ease in-out suits a move that both starts and ends at rest, like a slow orbit between two framings. Ease in alone, starting slow and ending fast, should almost always be followed by a cut, because a shot that ends at full speed and simply stops looks like a dropped frame.

Beware of curves that kill the middle

Strong exponential easing spends most of the duration nearly stationary and then covers the distance in the final moments. Over a short beat that reads as snappy; over a segment longer than about a second it reads as broken, because the viewer stares at a still image for most of the shot. For long opening and closing moves, a gentler quintic or cubic curve keeps something visibly happening the whole time.

Match easing across a sequence

If shot one settles softly and shot two arrives with a hard stop, the video feels assembled from different projects. Pick one arrival curve and reuse it. Variation should come from duration and distance — a slow, small move versus a quick, large one — not from a different curve every time.