Use of tangible and augmented reality models in engineering graphics courses

Engineering graphics courses are typically a requirement for engineering students around the world. Besides understanding and depicting graphic representation of engineering objects, the goal of these courses is to provide students with an understanding of the relationship between three-dimensional (3D) objects and their projections. However, in the classroom, where time is limited, it is very difficult to explain 3D geometry using only drawings on paper or at the blackboard. The research presented herein aims to develop two teaching aids; a tangible model and an augmented reality (AR) model, to help students better understand the relationship between 3D objects and their projections. Tangible models refer to the physical objects which are comprised of a set of differently shaped pieces. The tangible model we developed includes eight wooden blocks that include all the main geometrical features with respect to their 3D projections. The AR models are the virtual models which can superimpose 3D graphics of typical geometries on real-time video and dynamically vary view perspective in real-time to be seen as real objects. The AR model was developed using the ARToolKitPlus library and includes all the geometrical features generally taught in engineering graphics courses or technical drawing courses. To verify the effectiveness and applicability of the models we developed, we conducted a user test on 35 engineering-major students. The statistical results indicated that the tangible model significantly increased the learning performance of students in their abilities to transfer 3D objects onto two-dimensional (2D) projections. Students also demonstrated higher engagement with the AR model during the learning process. Compared to using the screen-based orthogonal and pictorial images, the tangible model and augmented reality model were evaluated to be more effective teaching aids for engineering graphics courses.