Designers of IT environments often have preconceived ideas about future use of their tools. We benefited from circumstances that permit to observe two IT environments dedicated to creative design assistance in architectural domain. These environments were separately used by the same kind of users performing the same task. But their developments are based on two different principles of assistance in architectural creative design. From the observation of pairs of students in architecture, it appears that the use is partly in line with developers' expectations, but also that they mobilize various resources in order to maintain their own control on design process. This experiment allows users to express their perception of what is like to be a creative designer in architecture.