New computer-aided design tools applied on engineering design education A. Martin-Erro (1), M. Dominguez (1), M.M. Espinosa(1)   (1) UNED-ETSII (Ingeniería del Diseño)

1. Introduction   Computer aided design is applied worldwide and for all design activities . CAD was then included into the engineering curricula and an abandon of use of paper and pencil as it was considered as obsolete. That meant a trend for engineers to apply CAD to every drafting and design tasks, since conceptual to detail. Sketching practice was also reduced. The consequences of this CAD abuse and sketching abandon are a decline of spatial abilities and visual thinking skill, which are essential for engineering design practice. In addition, many graduate engineers has a great CAD knowledge but a poor ability to develop or communicate technical ideas on paper.

1. Introduction Sketching vs. CAD Why sketching is necessary 1. Introduction Sketching vs. CAD   Why sketching is necessary? CAD evolved to ease designer´s creative work (better user-friendly interfaces), but it does not fulfil creative requirements. CAD is not adequate for visual problem solving activities, which sketching does, as it also helps develop spatial abilities. Sketching CAD externalization GOOD POOR imprecise data design variants

  1. Introduction Corrective actions · Spatial abilities Fast Remedial courses (Martin Dorta, 2008) (Contero et al,2005) · Sketching practice fostering (Company, 2005) · Proper use of CAD (CAD is not a conceptual design tool!) For earlier design tasks, immediate action should be the return of paper and pencil, but future engineer needs to use computers, even at these stages. Advantages of computers from paper sketching are to be into consideration

1. Introduction There are design applications other than CAD to be considered to fulfil future design engineer´s needs These tools follows a different metaphor, some of these directly related to creative activities.

1. Introduction Computer-aided sketching (SBIM) · Resembles paper and pencil sketching practice. · Transforms 2D sketches into 3D models by various methods (reconstruction, recognition) · Contero et al (2005) studied effect of some specific Sketch-based applications are especially promising, because they improve students’ sketching ability while reinforcing their visual thinking , showing that it can be “an appealing alternative to classical paper-and-pencil exercises”. · Currently immature: “still less usable than paper and pencil sketches and with no significant improved functionality. More work is required for SBIM user interfaces ” (REGEO-UJI).

1. Introduction Digital Sculpting · Sculpting metaphor · Based on free mesh deformation of a geometric model · Currently applied by digital artists and industrial designers · Closer to artistic production than to CAD workflow

CSG free solid modeling A modeling tool for creating, presenting and communicating ideas through three-dimensional representation. Can be used to create anything, from simple 3D shapes to complex models, thereby promoting creativity (Fischer et al., 2005). Enables users to build and modify 3D models quickly and easily. Some studies to specific CSG free solid modeling (Sketchup) related on education Liveri (2012) , Martin-Dorta (2008) Kurtulus (2010)

1. Introduction Objective Study mentioned new computer aided design tools, more focused to creative work than CAD, for its application on engineering education

2. Experimental   · Usability study We performed a test of use of these tools compared to traditional sketching. (Does it reduce or benefit spatial abilities, visual thinking?) 1) help to generate mental 3D images? 2) develop ideas graphically? 3) express concepts easy? (Does it support creative thinking?) 1) Easy and quick geometry generation (externalization). 2) no need of parametric data for geometry generation ( imprecise data). 3) Work with design alternatives (design variants).

3. Results SBIM Pros: Best at freeform shapes generation 3. Results   SBIM Pros: Best at freeform shapes generation. Quick and easy modeling. (good externalization.) intuitive and flexible interface, but at 2D level (which in the other hand, it does not limit spatial abilities). Cons: limited geometry modification (few lateral thinking) . Generates few detailed shapes (poor mesh)

3. Results   Digital Sculpting Pros: easy and intuitive model editing (supports design variants and so lateral thinking). Best to generate freeform shapes. Cons: hard to generate an idea“from scratch” as it needs a starting 3D model (poor externalization).

3. Results   CSG free modeling (Sketchup) pros: good and quick for 3D regular shapes. Easy to modify and combine solids. (good at concept variant generation-support lateral thinking). cons: limited to free form and complex shapes generation (limited externalization of any design).

Traditional Sketching 3. Discussion   According to creative requirements, results showed that each studied application does not comply with these as traditional sketching does. SBIM DS CSG (Sketchup) Traditional Sketching externalization MEDIUM POOR GOOD imprecise data design variants

3. Discussion   Unless SBIM, which works from 2D to 3D, DS and CGS does not benefit spatial abilities. In the other hand, all of these tools helps visual thinking as it means a source of inspiration to develop ideas visually as well as to express these ideas.

4. Conclussions   These tools has creative features and does not limitate spatial abilities nor visual thinking as CAD does. However, are quite far from traditional tools (paper sketching). Advantage goes it lets work with geometric models at problem solving and so concept ideation. Currently, these systems cannot substitute traditional sketching, but means an interesting support in order to quick implement design ideas into a computational environment, as a complementary tool, and a better alternative to use CAD at earlier design stages. Proper use of CAD must considered at the university , as well as new computer aided design tools, such as digital sculpting, computer aided sketching, must be taken into consideration. A model to integrate the software into of engineering design teaching shall be recommended by combining use of sketching, CAD and new tools, according to each engineering design task .