Classic design activities start from functions and end defining the product structure. The literature offers tools to model the cognitive aspects of these activities. The analysis of recent design activities highlights inadequacies of these tools because of the variety of starting points and goals. This research develops a descriptive framework, the X for Design - XfD, to model different design activities showing any combination of starting points and goals, by putting the existing FBS framework into relationship with the product experience and human behaviour in design concepts.
