Rotoscoping

Rotoscoping is animation drawn over live action. Amiga Format’s digitiser feature put it in one sentence in 1992: “drawing an animation over live action, so that it looks like a cartoon but moves more realistically”, and named the two places its readers would know it from — the cartoon film Lord of the Rings and the game Prince of Persia. In games the technique is tied to a short list of titles from a shorter list of people: Jordan Mechner’s Karateka (1984) and Prince of Persia (1989), and Delphine Software’s Another World (Eric Chahi, 1991) and Flashback (1992).

Fast facts

What it is: tracing over film or photographs of a real person to produce animation frames.
What it buys: movement with weight and timing that hand-drawn sprites of the period lacked; reviewers reached for “fluid”, “lifelike” and “silky-smooth” every time.
What it costs: frames. Delphine’s answer in Flashback was a character “animated at a rate of 24 frames per second”; Chahi’s answer in Another World was to draw the traced figures as polygons, so that a minutes-long animated intro fitted in 95 kilobytes.
Not the same as digitisation: a rotoscoped sprite is drawn by an artist over the reference; a digitised sprite is the photograph itself, reduced to the machine’s palette. See Digitised Sprites.

Karateka (1984)

Karateka was in the shops by the spring of 1984 — Enter’s review that May praised its “superb animation” — and Brøderbund’s 1985 advertisement sold the method behind it. Under the heading “The making of Karateka” it described designer Jordan Mechner as “a karate enthusiast and a stickler for realism” who “used film clips of the first karate masters as a guide for the moves used in the game”, so that the “carefully detailed, animated figures perform all the moves of real martial arts combat with stunning realism”. The game shipped for the Apple II, Commodore 64 and Atari 8-bit machines.

Prince of Persia (1989)

For Prince of Persia the reference footage was Mechner’s brother. Amiga Format told the story twice, in 1992 and again in 1994: “the game’s designer took pictures of his brother jumping around the flat and drew the animation for the main character based on that”, and “the animator took photos of his brother jumping around the house and then traced over them to produce a realistic sprite animation for the main character”. The result became the yardstick. COMPUTE’s 1994 beginner’s guide called the game “widely considered a milestone in the genre” and “a stunning showcase of rotoscoped animation, featuring incredibly fluid and lifelike character animation”, and Amiga Computing was still recommending it against Flashback in the summer of 1994, “even if it is showing signs of old age”.

Another World (1991)

Eric Chahi’s Another World — Out of This World in the United States — is rotoscoping without bitmaps. The One’s preview described “a sophisticated animation system which uses polygons rather than bitmapped artwork”, created by Chahi and “already employed to a limited extent in Cruise For A Corpse, where it allowed the use of special effects such as zooms and scaling”. The saving was the point: the intro sequence “requires just 70 Kilobytes for the animation data, and 15 Kilobytes for the program — that’s just 95 Kilobytes in total. An animation of similar complexity and length rendered with traditional bitmapped artwork would take up an entire disk!” ACE reported that Chahi “has spent two years labouring away on this one”.

The reference for the polygons was Chahi himself. Club Nintendo’s coverage of the SNES version explained that “the programmer, Eric Chahi, was photographed in various poses and the resulting pictures were then digitised. The digitised photos were then traced using a paint-box programme, thus creating an accurate and realistic portrayal of the central character.” Interplay’s catalogue copy for the PC release made the same connection from the other side: “the use of polygon graphics allows the game to generate real-time, rotoscoped animation in fluid cinematic zooms, pans, close-ups, and scaling”.

Flashback (1992)

Flashback returned to drawn sprites and made 24 frames a second the selling point. Amiga Format’s preview relayed Delphine’s claim that the game was “six-times larger” than Another World with “a main character animated at a rate of 24 frames per second — which is the same as most animated movies”, achieved by rotoscoping, “where they film a real actor going through all the necessary movements, and they then transfer those movements to the Amiga”. U.S. Gold’s advertisement in Computer Gaming World said the same in the first person: “We filmed real actors in motion. Then we brought everything to life on the computer through rotoscoping, the digitization and retouching of live action film — at 24 frames a second!”

Reviewers agreed with the advert. Computer Gaming World: “impressive animation derived from 24 frames-per-second rotoscoping — a truly uncanny thing to watch! Conrad jumps, rolls, twists and runs with ease and grace.” AmigaWorld drew the line between the two Delphine games: “Gone are the earlier game’s polygon constructs; they’ve been replaced with rotoscoped actors and hand-drawn backdrops.” Amiga Power’s games-of-the-year round-up settled for “the rotoscoped characters that move like real people”, and COMPUTE called the technique “similar to that used in Jordan Mechner’s Prince of Persia series”.

Rotoscoping vs digitisation

The two are often confused because both start with a camera:

Technique	Method	Look
Rotoscoping	An artist traces over film or photographs	Drawn, stylised; moves like the reference
Digitisation	The photograph itself is captured and reduced to the palette	Photographic, sometimes uncanny

Prince of Persia, Another World and Flashback are rotoscoped. U.S. Gold’s Flashback advert blurs the line on purpose — “the digitization and retouching of live action film” — but the sprites on screen are drawn. For the photographic family see Digitised Sprites; for the technique’s successor, Motion Capture.

Animation from life