ABSTRACT
New user-interface design methods become necessary when there is a need to capture particular properties of interactive systems, which cannot be explicitly or suffi ciently represented through existing design approaches.1 For instance, the identifi cation of graphical constraints among interface objects is not usually carried out in the context of task analysis. Hence, if the explicit representation of graphical constraints is necessary (e.g., as an input to the implementation phase), a dedicated design process needs to be carried out for the extractioan of such necessary design information. Also, in situations where a single design approach does not fulfi ll the requirements of the design process, the combination of alternative design techniques is applied, leading to hybrid design methodologies (e.g., combination of task analysis and graphic design methods).
