CAD model creation and alteration: A comparison between students and practicing engineers

Abstract

Computer-aided design (CAD) is a powerful and ubiquitous tool in the modern engineering environment. CAD databases are used throughout the development process, but to take full advantage of the functionality provided by modern CAD tools requires a skilled user. Students tend to be taught CAD in a manner that focuses on declarative skills and knowledge that is limited to creating geometry in a specific program. This is in contrast to the procedural knowledge associated with experts. Comparing student modeling procedure to that of practicing and experienced engineers could inform CAD educational activities. The results of an exercise performed by 30 practicing engineers and 107 students are presented. The exercise consisted of creating and altering a CAD model of moderate complexity. Both students and practicing engineers were split into groups and asked to create the part with altering goals: one group's goal was to create the part as quickly as possible; the other's goal was to create the part so that it could be easily altered. These initial parts were then altered by others in the opposing group. Model attributes and derived quantities for both groups are tabulated for both populations. As expected, student modelers required more time to complete the initial modeling and alteration activities. Students used more, simpler features to create their models (in both groups). The practicing engineers tended to produce models that followed commonly described proper modeling procedures. During the alteration process, students were more likely to delete features as opposed to alter them. Exercises are suggested to encourage student modeling procedure more in line with that of the experts. Student and practicing engineers also had slightly differing opinions regarding which modeling procedures would be beneficial. © 2011 American Society for Engineering Education.