Creating visual effects for Dr Who using computer-generated images and programs
More recent episodes of Dr Who make extensive use of computer programming, particularly for controlling highly realistic visual effects (VFX) using computer-generated images (CGI).
A 3D model of a Dalek is drawn using computer software. Multiple copies are created and positioned automatically using a simple script (program). This allows for much greater numbers of Daleks to be seen on screen than when full-sized physical models are used. Editing the code, for example changing from a random number to a set number, changes the behaviour of the whole Dalek army. Incorporating human actors is done using a green screen (chroma key) effect, in which background pixels of recorded video are replaced by the computer-generated images.