Situation Analysis of Design Tasks for CAD Systems

There has been little empirical research on the human aspects of CAD systems. In this paper observations on the analyses of designer activities are presented, by using a systems design approach. The paper concentrates on situation analysis and subsequent allocation of system tasks. A situation analysis was carried out in two design departments. The analysis consisted of a formal system description and a reconstruction interview. During the interview the previous week's activities were reconstructed with the help of photographs of the drawing board and protocols completed by design draughtspersons. This procedure was used for six design projects. In this study the technique of the reconstruction interview proved to be very useful and informative, and enabled three general conclusions to be made. First, designers liked the initial design phase and their responsibility for the final result. Second, they disliked the activities associated with drawing as well as the project documentation phase. Third, they preferred to work with two or more drawings on the drawing board. A number of frequent tasks could be identified, for example, large scale manipulation within and between drawings. In the final section, an example of a global allocation of system tasks for the design of a CAD system is given.