Beta. Off by default: the arm moves to its target with a smooth ease-in/ease-out (linear smooth), capped by Max speed. When enabled, it applies when the arm moves toward a target by itself (Home, playback, Blocks). Jogging and dragging follow your hand directly. Short moves never reach full speed, so the trapezoid becomes a triangle. S-curve also limits jerk (how fast acceleration changes), so starts and stops are gentler. It takes a little longer.