Slow In / Slow Out Mastery The Physics Principle Objects in the real world don't move at constant speeds—they accelerate from rest and decelerate to stops. Slow in/slow out (also called ease in/ease out) captures this fundamental truth. Without it, animation looks mechanical. With it, motion feels alive. Core Theory Slow Out (Ease Out): More drawings clustered at the start of a movement. The object accelerates away from its starting position gradually. Slow In (Ease In): More drawings clustered at the end of a movement. The object decelerates into its final position gradually. Linear motion :…