This paper presents an application of Augmented Reality for improving spatial abilities of engineering students. An augmented book called AR-Dehaes has been designed to provide 3D virtual models that help students to perform visualization tasks to promote the development of their spatial ability during a short remedial course. A validation study with 24 Mechanical Engineering freshmen at La Laguna University (Spain) has concluded that the training had a measurable and positive impact on students' spatial ability. On the other hand, results obtained using a satisfaction questionnaire illustrate that AR-Dehaes is considered an easy to use, attractive and very useful technique for students. AR-Dehaes has proved to be a very cost effective tool insofar as it only required an ordinary PC with a webcam to be used.

An engine that automatically reconstructs a large variety of polyhedral, origami and wire-frame objects from single-view sketched drawings generated in a calligraphic interface is presented. The engine has two stages. An innovative optimisation-based line-drawing beautifier stage is introduced to convert rough sketches into tidied-up line drawings. Optimisation-based 3D reconstruction follows. Solutions are provided with which to overcome the problems associated with earlier approaches to optimisationbased 3D reconstruction. Suitable adjustments in the optimisation algorithms are proposed; simple and efficient tentative models are introduced, and current regularities are categorised in order to allow the objective function to be simplified. All three actions help to prevent local optima and improve the computational efficiency of optimisation-based 3D reconstruction. They all proved to be effective techniques to reduce the typical failure rate of optimisation approaches. A discussion of results that validate the engine is also provided.4

This paper presents the results of a pilot study designed to evaluate the feasibility of launching a fast remedial course based on 3D CAD modeling for improving spatial abilities of engineering students. The study was carried out with civil engineering students at the University of La Laguna (Spain) during the 2006–2007 academic year. The main requirements in the design of the course were: short and intensive (12 hours worth of work during 3 weeks), attractive for the students, and use of free 3D CAD modeling software. The chosen software was Google SketchUp. Exercises based on practice with this modeling tool had a measurable and positive impact on students' spatial ability, measured by both MRT and DAT:SR tests. The results are then compared to our previous studies at La Laguna University based on classic pencil and paper exercises, multimedia Web‐based applications, and exercises using a sketch‐based modeling application.

We analyze the importance of visualization skills in engineering education, proposing a dual approach, based on computer graphics applications using both Web-based graphic applications and a sketch based modeling system, to improve these capabilities. AbstractWe analyze the importance of visualization skills in engineering education, proposing a dual approach based on computer graphics applications using both Web-based graphic applications and a sketch based modeling system to improve these capabilities.With the aim of addressing acquisition of spatial reasoning, we first analyze the importance of spatial abilities in the context of engineering education and the available techniques for evaluating these abilities from a psychological point of view. Then we review some Web resources conceived specially to help students to improve their spatial abilities and present two educational applications, eREFER and eCIGRO, designed with two main objectives: drawing student's attention and fostering two important skills for the future engineers: freehand sketching and understanding the relationship between orthographic and axonometric views. Finally we present a pilot study carried out at La Laguna University using these tools, ending with some conclusions KeywordsSpatial reasoning, engineering education, sketch based modeling.Data graphics are usually the best method for analyzing and communicating quantitative information 1 . But, like any means of communication it can deceive if not used correctly 2 . Hence, visualization skills are required to be able to make and read good-quality graphics. Engineers need general-purpose data graphics, like other groups such as scientists and economists. However, their requirements go far beyond general data graphics up to engineering graphics, which focus on geometrical design, i.e. fixing the geometry that satisfies all the design specifications and communicating it to others. This is currently done through the so-called "design-by-drawing" method, which is currently supported by the body of knowledge known as descriptive geometry and a well-defined set of drawing standards. Commercial 2D CAD applications provide electronic support for it. Nevertheless, since the end of the 80's, 3D CAD applications opened the door to a new "design-by-virtual models" paradigm that is progressively replacing design-by-drawing.Apprenticeship of engineering graphics is a crucial task in both, design-by-drawing and design-by-virtual models approaches, and it is as complex as all languages. For instance, it includes learning non-formalized rules, like the "simplicity criterion" sometimes expressed in the following terms: "the geometrical shape represented is the simplest one among all those whose projection matches the drawing". Furthermore, non-geometrical and a priori conventions (like graphical semantics and visual stimuli described in Gestalt rules) are implicitly integrated in technical drawings, as they are in all graphical communication 2 . In addition, explicit conventions (standards) have to be ...

CAD model quality in parametric design scenarios largely determines the level of flexibility and adaptability of a 3D model (how easy it is to alter the geometry) as well as its reusability (the ability to use existing geometry in other contexts and applications). In the context of mechanical CAD systems, the nature of the feature-based parametric modeling paradigm, which is based on parent-child interdependencies between features, allows a wide selection of approaches for creating a specific model. Despite the virtually unlimited range of possible strategies for modeling a part, only a small number of them can guarantee an appropriate internal structure which results in a truly reusable CAD model. In this paper, we present an analysis of formal CAD modeling strategies and best practices for history-based parametric design: Delphi's horizontal modeling, explicit reference modeling, and resilient modeling. Aspects considered in our study include the rationale to avoid the creation of unnecessary feature interdependencies, the sequence and selection criteria for those features, and the effects of parent/child relations on model alteration. We provide a comparative evaluation of these strategies in the form of a series of experiments using three industrial CAD models with different levels of complexity. We analyze the internal structure of the models and compare their robustness and flexibility when the geometry is modified. The results reveal significant advantages of formal modeling methodologies, particularly resilient techniques, over non-structured approaches as well as the unexpected problems of the horizontal strategy in numerous modeling situations.