Prospero, Manuel JoaoMessina, Luiz AryA.A.G. Requicha2015-09-292015-09-2919861017-4656https://doi.org/10.2312/eg.19861015Dialogue control and dialogue object structures are the outlined concepts developed in this paper. Phases of a CAD-Process are presented to show an outstanding application for the concepts The use of logic programming dealing with geometric structures performs the innovative elements to enable the construction of more flexible graphical interfaces, which can operate as information collectors and structure checks in design processes.10.2312/eg.19861015