Choose easing from what an object is doing

Use one illustrative square moving from the left edge to the center. Before drawing a curve, state its verb: arrives, passes, settles or responds. Each verb implies a different relationship with the destination. A square passing through the center should not slow as though the center were its home.

Create a decision card with action, start condition, destination, speed behavior, stop condition and potential misreading. Keep the same square, distance and background for the comparison so that viewers can judge the motion rather than changes in composition.

Arrival: the square moves toward the center and decelerates into a stable stop. Pass-through: it maintains a coherent travel rhythm across the center and exits beyond the frame. Settling: it begins near its resting position, makes a small corrective movement and stops. Response: a visible trigger occurs first, then the square changes position or state.

In the illustrative response study, a labeled signal light appears before the square moves. If the square begins early, the viewer may infer anticipation or an unrelated event. Record the trigger frame and the first movement frame. Timing is part of the explanation, not only an aesthetic choice.

A long slowdown before crossing an invisible boundary can imply hesitation. A strong overshoot can suggest elasticity, instability or playfulness. Those impressions may be useful, but they should fit the object’s role. Do not use the same bouncy arrival for a measurement marker and a playful mascot without considering what each means.

For the educational square, choose a direct decelerating arrival and a still hold. Reserve the elastic version as a counterexample. If the square represents a real mechanism, have the subject reviewer confirm whether the motion is a simplified illustration or physically meaningful; style should not quietly change the mechanism.

First approve the geometric path with simple timing. Then compare easing alternatives while preserving its endpoints and total interval. This isolates the decision. Check the frame just before stopping for a snap, and inspect the next few frames for unintended residual drift.

When a label rides with the object, consider whether it needs a separate reading hold after movement. A faster arrival can create more still reading time, but it may also make the entrance too abrupt. For a restrained alternative, use a direct state change or a small bounded movement. Record the chosen action and rationale so later retiming preserves its intent.