CGI

CGI or Computer-Generated Imagery is the field of modern animation in which pictures are developed by programs in enormously powerful computers, animated and then transferred to visual media for viewing. Its earliest examples date from the late 1960s and the Disney Company used it strikingly for the title sequence of The Black Hole in 1979. By 1989, James Cameron used it to create the "water creatures'" in his film The Abyss. In the years since, advances in computer power and programming have reduced the costs of CGI to the point where it is less expensive than traditional hand-drawn cel animation and modern animated movies usually use the computer techniques.

Because CGI was prohibitively expensive for major movies until 1989, there are no known instances of it in the 1963-1989 Doctor Who, It has been used extensively in the revived series, beginning with the Nestene Consciousness in the first episode of the modern series, Rose.