Grounding animation in the real world.
In 1915, animator Max Fleischer patented the first rotoscope. Projecting live-action film of a clown (his brother Dave in costume) onto a glass panel, Fleischer then traced the figure frame by frame on paper in order to create more life-like animation. Using this animation technique, Fleischer created the short film series Out of the Inkwell and made his brother’s clown character (Koko the Clown) famous. Fleischer would go on to create other classic animated characters like Popeye and Betty Boop. He used rotoscoping to make their dance moves look like those of professional dancers. He also used rotoscoping to achieve surprising realism in the first Superman animated series.
After Fleischer’s patent expired, Walt Disney used his rotoscoping technique. Actors performed scenes and, from that footage, their movements were rotoscoped to use as reference material for many films, starting with Snow White and the Seven Dwarves.