In complex systems, the human–machine interface is typically computerized. The term human–computer interface refers to this kind of system.
The engineering of the human–machine interfaces is by considering ergonomics (Human Factors). The corresponding disciplines are Human Factors Engineering (HFE) and Usability Engineering (UE), which is part of Systems Engineering.
Tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the expression Graphical User Interface for human–machine interface on computers, as nearly all of them are now using graphics.
Primary methods used in the interface design include prototyping and simulation.