Motion Design Principles

This is the taste layer. It decides how something should move so it reads as polished and intentional instead of janky, floaty, or cheap. It does not write the code that plays the motion — once you have decided the curve, the timing, and the arc, that decision is the input to a directing/render skill (for product video, hand it to product-demo-director) or to your CSS/JS transition (for UI). Keep the two jobs separate: this skill owns the judgment; the directing skill owns the orchestration and mechanics.

Fire on anything about how motion feels: "make this less janky", "smoother", "more polished", "more alive", "the easing is off", "this looks cheap", "should I ease-in or ease-out", "spring or interpolate".

When to use a sibling instead

This skill is the curve/timing/arc judgment only. Defer when the real question is: