Ferran Naya

Improving visualization skills in engineering education

This article analyzes the importance of visualization skills in engineering education. It proposes a dual approach based on computer graphics applications using both Web-based graphic applications ...

Computer-aided sketching as a tool to promote innovation in the new product development process

Sketching is an established part of engineering culture. Sketches assist product designers during the creative stages of design and help them to develop inventions. Paper-and-pencil sketching is highly useful but lacks functionalities, mainly because it is disconnected from the rest of the (computer-aided) design process. However, CAS tools are not yet as usable as paper-and-pencil, although they provide full integration with the subsequent phases of the design processes (CAD, CAE, CAM, etc.) and other interesting functionalities. We desire computer-aided sketching (CAS) tools which furnish users with the sketching environment they require to make full use of their conceptual design and innovation talents, while providing full integration with the subsequent phases of the design processes (CAD, CAE, CAM, etc.). In this paper we discuss the importance of sketching in conceptual design, we review the current situation of engineering sketching, and we then analyze the main characteristics which a successful and fully integrated CAS tool should include. We consider CAS, not as a single problem, but as at least three: thinking, prescriptive and talking sketches require different approaches to functionality. Finally, we present the current state of the art in CAS tools by describing the main features and outstanding problems of our own applications.

CIGRO: a minimal instruction set calligraphic interface for sketch-based modeling

Although CAD systems have evolved considerably in functionality, expressiveness and modeling power over the last decades, their user interfaces are still tied to legacy principles and are not suited to the initial stages of product development. They exhibit steep learning curves, cumber-some and overly structured dialogues, including hundreds of commands. While much of this functionality may be required by the sheer complexity of the tasks these systems are designed to help, we believe the user interface could benefit from simpler paradigms based on sketching and drawing to reduce unneeded complexity, especially in the conceptual design phase. In what follows, we present the CIGRO system that provides a reduced instruction set calligraphic interface to create polyhedral objects using an incremental drawing paradigm evocative of paper and pencil drawings. Users draw lines using an axonometric projection, which are automatically beautified and connected to existing elements of the drawing. Such line drawings are then converted to a three-dimensional model through a reconstruction process guided by an axonometric inflation method.

ParSketch: a sketch-based interface for a 2D parametric geometry editor

ParSketch is a software prototype to evaluate the usability and functionality of a sketching interface aimed at defining 2D parametric sections. Currently, ParSketch interprets strokes which can be recognized as geometry (line, arc, circle, ellipse, or composed entities that are automatically segmented into those basic entities), or graphic gestures representing constraints (dimension, parallel, perpendicular, tangent, concentric, horizontal or vertical). From the functionality point of view, ParSketch compares to current commercial parametric CAD applications, as it offers many of the features provided by such applications. A theoretical analysis of the efficiency component of usability is provided that justifies the potential capability of sketching interfaces to compete with classical WIMP applications. Finally, a usability study is presented, which makes special emphasis in the satisfaction component of usability.

Parametric Freehand Sketches

In this paper we present the 2D parametric freehand sketch component of an experimental prototype called GEGROSS (GEsture & Geometric ReconstructiOn based Sketch System). The module implements a gesture alphabet and a calligraphic interface to manage geometric constraints found in 2D sections, that are later used to perform modeling operations. We use different elements to implement this module. The geometric kernel ACIS stores model data. The constraint manager 2D DCM handles restrictions. Finally, we use the CALI library to define gestural interfaces. In this paper we present a strategy for integrating these tools, and a calligraphic interface we developed to provide dimensional controls over freehand sketches. Our system allows users to build simple sketches composed by line segments and arcs, which are automatically tidied and beautified. Proportional and dimensional information over sketched parts is provided by handwriting their corresponding sizes.

Sketch-Based Interfaces for Parametric Modelling

Sketching is still widely used by designers and engineers as it continues to be a useful and powerful tool that helps designers during the conception of a new product (Tversky, 2002). If engineers and designers generally use sketches the question is, why sketching is not integrated in the digital design process? Available Graphical User Interfaces (GUI) for CAD applications are still by and large constrained by the WIMP (Windows, Icons, Menus and Pointing) paradigm and current commercial CAD systems not support sketch-based design. Therefore, the problem is that the sketches continue to be unplugged to the rest of the design process. In other words, in spite of recent advances in Computer Aided Design, current CAD tools are not well suited to the initial design stages of product development, because many techniques and idioms characteristic of hand-made drawings cannot be used directly in CAD systems. To sum up, there is a disconnection between sketching and CAD tools in the new product development process and true Computer-aided Sketching (CASk) tools are required. During last decades different research lines have been explored to improve the humancomputer interface in CAD systems. In this context, some CASk systems have been developed to support freehand drawings as a way to create and edit three-dimensional geometric models. These advanced CASk systems try to provide more functionality than paper or a whiteboard, giving an added value to sketching on a digital environment. This extra functionality usually has been directed either to improve the graphic quality of the sketch by means of a beautification process or it has been oriented to automatically transform the 2D sketch into a 3D model. Interest in CASk systems has increased in the last years as new hardware devices such as Tablet-PCs and LCD graphics tablets have been launched to the market.

Smart sketch system for 3D reconstruction based modeling

Current user interfaces of CAD systems are still not suited to the initial stages of product development, where freehand drawings are used by engineers and designers to express their visual thinking. In order to exploit these sketching skills, we present a sketch based modeling system, which provides a reduced instruction set calligraphic interface to create orthogonal polyhedra, and an extension of them we named quasi-normalons. Our system allows users to draw lines on free-hand axonometric-like drawings, which are automatically tidied and beautified. These line drawings are then converted into a threedimensional model in real time because we implemented a fast reconstruction process, suited for quasi-normalon objects and so-called axonometric inflation method, providing in this way an innovative integrated 2D sketching and 3D view visualization work environment.

Accessibility and tangible interaction in distributed workspaces based on multi-touch surfaces

Traditional interaction mechanisms in distributed digital spaces often fail to consider the intrinsic properties of action, perception, and communication among workgroups, which may affect access to the common resources used to mutually organize information. By developing suitable spatial geometries and natural interaction mechanisms, distributed spaces can become blended where the physical and virtual boundaries of local and remote spaces merge together to provide the illusion of a single unified space. In this paper, we discuss the importance of blended interaction in distributed spaces and the particular challenges faced when designing accessible technology. We illustrate this discussion through a new tangible interaction mechanism for collaborative spaces based on tabletop system technology implemented with optical frames. Our tangible elements facilitate the exchange of digital information in distributed collaborative settings by providing a physical manifestation of common digital operations. The tangibles are designed as passive elements that do not require the use of any additional hardware or external power while maintaining a high degree of accuracy.

On the Integration of Tangible Elements with Multi-touch Surfaces for the Collaborative Creation of Concept Maps

Collaborative creative work in small groups can significantly improve learning, particularly when supported by concept maps. Although useful in collaborative environments, most applications for the development of concept maps are designed for personal or small tablet computers, which can limit student communication in a team setting. In addition, the use of these applications usually requires training periods that may reduce the time allotted for regular learning activities. In this context, digital tabletops can effectively promote collaboration and face-to-face communication by providing a large horizontal interactive surface. However, despite its large size, a single tabletop cannot accommodate more than three or four students. Therefore, collaborative learning spaces and work groups with multiple devices become necessary. In such scenarios, the exchange of information between groups is critical. In this paper, we propose the use of tangibles, as a natural mechanism to exchange information by using a distributed collaborative concept map application.