ion level. Due to these conflicting arguments, it is difficult to make a definitive statement of the value of hand sketching versus computer generated representations throughout all design phases. The advantages and disadvantages of each method vary as the designer progresses through the design process. A case study is conducted to observe a group of senior level mechanical engineering students and explore their use of sketching vs. CAD as the students completed a semester long industry sponsored design project. The case study presented in the paper aims at understanding the selection and implementation of various CAD tools in the design process by novice engineers. Referring back to a model of the design process (Pahl & Beitz, 1995) and relating it to this case study (Section 2), it is seen that the use of CAD in the planning and clarification of the task step was inefficient (Section 3.1). The time spent modeling the original design exceeded the knowledge gained. This was especially apparent when compared to the knowledge that could have been gained through an abstract sketch (Section 3.2). CAD representations are exact, yet it is the inexactness of the sketch that can induce creativity (Utterback, 2006). Once the proposed solution was modeled in the sixth week of the design project changes were not made until the physical prototype was created (Section 3.3). The Veisz, Namouz, Joshi, Summers Disappearance of Sketching 8 fact that six weeks went by without any design change suggests that the group was fixated on the solution that they had modeled. The high level of detail in the model provided unsupported confidence that the solution is optimal. That is, until the model was mentally re-examined when the physical prototype fabrication and assembly began (Section 3.4). 1.3 Process of Creating Solid Models Although creating solid models may seem daunting and complex to an outsider or an inexperienced user, recent programs have made solid model creation more intuitive. There are three modeling approaches in which a solid model can be created (Zeid, 2005). A designer does not select an approach in designing; instead, the model most likely will contain a combination of the approaches: Primitive – uses “union, subtraction, and intersection” (Zeid, 2005) to create shapes, Features – combines steps of the primitive approach with user friendly commands like “create hole”, Sketching – allows sketched 2D shapes to be extruded, revolved, or swept to create 3D models. It is possible to create complex shapes in solid modeling packages using advanced functions (Mortenson, 1997); however a novice user will most likely not be introduced to such functions. Also, since initial geometry must be defined in order to generate complex features, the incentive, especially in the conceptual design phase is to avoid these functions altogether and construct using simple, symmetric shapes. The team members who were the predominant CAD users stated the following when asked whether they felt that CAD tools expanded or limited their
This paper describes and evaluates approaches to model and solve technical product configuration problems using different artificial intelligence methodologies. By means of a typical example, the benefits and limitations of different artificial intelligence methods are discussed and a flexible software architecture for integrating different solvers in a product configurator is proposed.
Product configuration is a key technology, which enables businesses to deliver and deploy individualized products. In many cases, finding the optimal configuration solution for the user is a creati...
