Rotoscoping is the process of drawing animation over live-action film.
Max and Dave Fleischer invented the process in 1915 to animate Koko the Clown of their Out of the Inkwell series, and later used it to animate Cab Calloway's dancing in three Betty Boop shorts, but the most famous Fleischer rotoscoping was done in the studio's Supermancartoons.Disney Studios had used rotoscoping from Snow White and the Seven Dwarfs (explaining the slightly different art style of said characters) all the way to 101 Dalmatians.
Rotoscoping has been used lightly (to create realistic movements for otherwise stylized characters) and heavily (nearly tracing an entire actor's movements, form, and facial expressions). The downside of heavy rotoscoping is that the animated actors tend to teeter on the edge of the Uncanny Valley.
More recently, computer technology has created new life for rotoscoping as a medium, allowing for much greater detail and smoother movement. Fully computer-generated characters are Serkis Folk, much like fully animated characters give it the Roger Rabbit Effect.
However, rotoscoping has a bad reputation among the animation community, including men such as Richard Williams, Milt Kahl, Shamus Culhane and John Kricfalusi, being percieved as a lifeless, poor substitute for character animation. Even Ralph Bakshi, a frequent user of it in his feature films, admits that he loathed using it and that it was only used due to his low budgets and inexperienced younger artists. In fact, Max Fleischer himself came to realize the limitations of the very device he created early on, opting for more creative use of character animation instead (although he didmakesomeexceptions).
Compare Motion Capture, which is how computers do it these days.
Done in Yellow Submarine for the "Lucy in the Sky with Diamonds" segment, using old live-action musical footage to striking effect.
The song "Sita's Fire" from Sita Sings the Blues, one of the 5 art styles used in the film (though this is only used for one song.)
Disney's most well-known use of it was the vehicles in 101 Dalmatians. They built models of the cars and trucks, painted them white with black "outlines" on the edges, shot them in stop-motion in front of a white background, and then photocopied the results directly onto the animation cels. They would continue to use this technique in The Aristocats and The Rescuers, largely using the exact same models.
The little-known, less-seen, and not-entirely-completed masterpiece Happy New Year, Planet Earth (never released owing to licensing and contractual issues). A Canadian cross between Heavy Metal and Yellow Submarine set to music by the band Klaatu, it is mostly rotoscoped.
Specifically averted in Lilo & Stitch. One of the special features shows the animation process of the opening hula dance scene, in which the animators watched footage of actual dancers and painstakingly animated the movements by hand; it's mentioned that they did this instead of rotoscoping it, because...um...Hard Work Fallacy?
An interesting case in The Great Mouse Detective. The gears inside Big Ben at the start of the climax were done in CGI, but were then traced onto paper by a computer, xeroxed onto cels and painted in.
Films – Live-Action
The lightsaber effects in the original Star Wars trilogy. Rotoscoping is still the word you would use to describe the prequel trilogy's lightsabers, but it's the modern computer-aided version.
Elena's animations look a little different from the rest of the Street Fighter III cast, largely because all of her animation was rotoscoped. This was probably done because capoeira may have been too daunting for the artists to hand animate convincingly.
Hotel Dusk: Room 215 and its sequel, Last Window. Actors and actresses are brought in, and they are filmed performing various movements. The most essential "frames" of their movements are then drawn over and spliced together to create the grainy, film-noir novel style.
The kiss scene between Blair and Angel in Wing Commander II was rotoscoped, with series creator Chris Roberts providing the basis for Blair's body.note The female providing the base body for Angel is unknown, however, but probably an Origin staffer at the time.
French/Canadian co-production Delta State is the first animated television series to be entirely rotoscoped, taking over 27 months to complete. This gives the show an... interesting look, to say the least.
Filmation's Star Trek: The Animated Series used rotoscoping in an interesting way: the footage of the USS Enterprise, used in establishing shots (and the title sequence), was achieved by taking the actual footage used in the original 1960s live action series, and then painstakingly recreating it in animation, frame-by-frame. They hold up pretty well.
Another Fleischer's feature-length cartoon, Mr. Bug Goes to Town, does this with human characters (who, however, appear very little).
Some Looney Tunes shorts used this; a few notable examples are in the climax of "Daffy The Commando" the climax scene of Hitler giving his speech, and in "Hollywood Steps Out" with some of the dancing celebrities.
The 1990 short "Box Office Bunny" uses it when Bugs, Daffy and Elmer dance a rap tune on a bubblegum-stained floor.
In 1967, Warner Bros. had merged with Seven Arts which had acquired the 1931-43 black-and-white Looney Tunes shorts from absorbing Guild Films, who in turn acquired them from Sunset Films (believed to be a W-B dummy distribution firm). At that time, W-B had 75 of those cartoons shipped to Korea to be rotoscoped – redrawn and painted in color. The tight deadlines and low budgets (all done on 6-field cels) rendered these color versions sloppy and unattractive.
King Features had the same thing done in 1986 with the Fleischer black-&-white Popeye cartoons.
The animation of Josie and the Pussycats performing in the opening of their 1970 Hanna-Barbera cartoon was rotoscoped.
Family Guy uses this on occasion, usually for complex dance sequences (such as the Jitterbug song "Jungle Love" and Peter performing "How I Feel" in "New Kidney In Town")
The notorious short cartoon The Magic of Oz has rotoscoping in one shot. Of Dorothy bending down. Given how poor the animation is, it's believable that they couldn't animate a character bending down, but it's quickly clear that they didn't know how to rotoscope properly either.