In CAD modelling, there is no one general standardised teaching-learning methodology. We use the strategic-learning methodology, maintaining design intent, fully aware that it is necessary to modify CAD models for their reuse. Questions concerning the thought processes of students when modelling with CAD and the strategies that they choose that best maintain design intent arise in the course of using the 3D modelling programmes. Our aim here is to determine the importance of adaptive expertise in the results of CAD models and, particularly, in one of its constructs: design intent. To do so, CAD-based experimentation took place over two years with 78 third-year students in the first year and with 53 third-year students in the second year from the subject module of Graphic Engineering, on the Degree in Mechanical Engineering of the University of Burgos (Spain). At the start of the year, the students conducted a survey to measure adaptive expertise. Subsequently, in the first year of experimentation, the students prepared various CAD models and the design intent was evaluated in one of them (a connecting rod or conrod), broken down into the skeleton, the structure, the modifications and the constraints. In the conrod exercise, the students also completed a questionnaire both before and after designing their models, which were analysed to detect the thought processes and the strategies that they had applied. In the second year of experimentation, design intent was incorporated in various exercises at the beginning of the year, in addition to the conrod. The main conclusion is that the correct division of the part into its pieces and adaptive expertise improved the results in relation to design intent in the CAD.
KEYWORDS: CAD learning, design intent (DI), adaptive expertise (AE), modification of CAD.
