Improvements in student spatial visualization in an introductory engineering graphics course using open-ended design projects supported by 3-D printed manipulatives

This work-in-progress reports changes in development of Spatial Visualization (SV) skills in students taking a first semester Engineering Design Graphics course modified to integrate geometric design modules supported by manipulative production through 3D printing. The ability to imagine three dimensional objects, to visualize them in rotated states, and to subsequently communicate them in 2D (sketches) and 3D space (virtual solid models) is a critical skill for engineers, and a large body of research has shown that the development of these skills is indicative of student success and persistence in engineering. Thus a course that due to its non-mathematical nature is often perceived as non-critical, in practice has demonstrated to be of high importance, as it is where decisions for exiting the program are made. The improvement of the development of SV skills during the freshman year has also received significant attention in the literature. The widespread teaching of 3D solid modeling software for the past two decades has introduced the capability to easily visualize objects in three dimensions, and typically constitutes the core content of the first design course. The flipside of this development is that the learning curve for the normally employed parametric solid modeling software is steep, and requires explicit instruction on the use of the software. Thus the course often has a focus on learning the software (which is typically done by requiring the students to learn the software by modeling existing 2D or 3D representations of an object), and not a design focus, where students develop a geometric solution to a stated problem without having any prior representation of the solution. The latter clearly requires the students to visualize the geometry of a solution before it is generated (either on paper or virtually in the computer). The work in progress presented here assesses differences in SV development in students enrolled in two sections of the same Engineering Graphics and Design course during the Fall 2015 semester; one that is taught in the traditional fashion and that represents a control group of 80 students, and a second section (76 students) modified to include two week-long and appropriately scaffolded geometric design exercises. Part visualization is supported by requiring the students to use and/or print 3D manipulatives of the parts that constitute the connecting elements to their freeform design problem, and to generate prototypes of their final solution in order to test assembly capability. The assessment tool utilized is the Purdue Spatial Visualization Test Rotations, administered in pre and post mode in both sections.