A conceptual design tool: Sketch and fuzzy logic based system

A real time sketch and fuzzy logic based prototype system for conceptual design has been developed. This system comprises four phases. In the first one, the system accepts the input of on-line free-hand sketches, and segments them into meaningful parts by using fuzzy knowledge to detect corners and inflection points on the sketched curves. The fuzzy knowledge is applied to capture user’s drawing intention in terms of sketching position, direction, speed and acceleration. During the second phase, each segmented sub-part (curve) can be classified and identified as one of the following 2D primitives: straight lines, circles, circular arcs, ellipses, elliptical arcs or B-spline curves. Then, 2D topology information (connectivity, unitary constraints and pairwise constraints) is extracted dynamically from the identified 2D primitives. From the extracted information, a more accurate 2D geometry can be built up by a 2D geometric constraint solver. The 2D topology and geometry information is then employed to further interpretation of a 3D geometry. The system can not only accept sketched input, but also users’ interactive input of 2D and 3D primitives. This makes it friendly and easier to use, in comparison with ‘sketched input only’, or ‘interactive input only’ systems. Finally, examples are given to illustrate the system

Particle Swarm Optimisation Based 3D Reconstruction of Sketched Line Drawings

The purpose of this paper is to demonstrate the application of particle swarm optimisation to line drawings reconstruction. The paper’s new contribution is the application of swarm intelligence in dealing with machine perception of sketch-based modelling interfaces. Traditional descent or gradient- based optimisation algorithms are not always practical in this context because of the severe numerical noise and ill-defined objective function of the optimisation-based reconstruction problem Our results point to particle swarm optimisation as a promising alternative.This work was partially supported by Universitat Jaume I (Plan 2002 de promoció de la investigació a l’UJI, Project P1-1B2002-08, entitled “From sketch to model: new user interfaces for CAD systems”)

Interfaz caligráfica para el diseño industrial

[ESP] En la actualidad continúan predominando las interfaces gráficas de usuario basadas en el paradigma WIMP (Windows, Icon, Menu, Pointing Device), lo que supone en ciertas ocasiones una excesiva rigidez para el diseñador en las primeras etapas del proceso de diseño, donde los bocetos realizados con lápiz y papel constituyen todavía la herramienta fundamental que permite expresar la creatividad del ingeniero. Debido a esto, la existencia de una interfaz gráfica de usuario basada en esbozos y gestos, resulta de gran interés, ya que facilitaría la comunicación y la creatividad del diseñador. Dentro de este contexto, el grupo de investigación REGEO ha desarrollado una aplicación para generar automáticamente modelos virtuales 3D, partiendo de dibujos a mano alzada en 2D. Esta aplicación automática se enmarca en la línea de lo que se denominan Interfaces Caligráficas. Aunque todavía queda mucho trabajo por hacer, la aplicación presenta mejoras en comparación con las formas tradicionales de modelado con ordenador, ya que la metodología utilizada para modelar es más familiar. Estudios preliminares muestran que nuestro sistema de modelado presenta ciertas ventajas respecto a los actuales sistemas CAD. [ENG]At present user’s graphics interfaces based on WIMP (Windows, Icon, Menu, Pointing Device) systems are still the most common technique, which in many cases involves an excessive stiffness for the user at the first stages of the design process,in which pen-and-paper sketches are the basic tools to express the engineer’s creativity. As a consequence, a user’s graphic interfaz based on sketches and gestures becomes relevant as it should help the designer’s communication and creativity. Within this context, the research team REGEO has developed a computer application to automatically generate 3D virtual models from freehand 2D drawings. This automatic application can be included in the research area of Calligraphic Interfaces. While much work remains to be done, the current application already shows gains with respect to more traditional forms of modeling in that it embodies a drawing approach familiar. Preliminary studies show that our modeling system compares favorably to commercial grade CAD systems.[ENG] At present user’s graphics interfaces based on WIMP (Windows, Icon, Menu, Pointing Device) systems are still the most common technique, which in many cases involves an excessive stiffness for the user at the first stages of the design process,in which pen-and-paper sketches are the basic tools to express the engineer’s creativity. As a consequence, a user’s graphic interfaz based on sketches and gestures becomes relevant as it should help the designer’s communication and creativity. Within this context, the research team REGEO has developed a computer application to automatically generate 3D virtual models from freehand 2D drawings. This automatic application can be included in the research area of Calligraphic Interfaces. While much work remains to be done, the current application already shows gains with respect to more traditional forms of modeling in that it embodies a drawing approach familiar. Preliminary studies show that our modeling system compares favorably to commercial grade CAD systems

Algorithmic Perception of Vertices in Sketched Drawings of Polyhedral Shapes

In this article, visual perception principles were used to build an artificial perception model aimed at developing an algorithm for detecting junctions in line drawings of polyhedral objects that are vectorized from hand-drawn sketches. The detection is performed in two dimensions (2D), before any 3D model is available and minimal information about the shape depicted by the sketch is used. The goal of this approach is to not only detect junctions in careful sketches created by skilled engineers and designers but also detect junctions when skilled people draw casually to quickly convey rough ideas. Current approaches for extracting junctions from digital images are mostly incomplete, as they simply merge endpoints that are near each other, thus ignoring the fact that different vertices may be represented by different (but close) junctions and that the endpoints of lines that depict edges that share a common vertex may not necessarily be close to each other, particularly in quickly sketched drawings. We describe and validate a new algorithm that uses these perceptual findings to merge tips of line segments into 2D junctions that are assumed to depict 3D vertices

Exploring local regularities for 3D object recognition

In order to find better simplicity measurements for 3D object recognition, a new set of local regularities is developed and tested in a stepwise 3D reconstruction method, including localized minimizing standard deviation of angles(L-MSDA), localized minimizing standard deviation of segment magnitudes(L-MSDSM), localized minimum standard deviation of areas of child faces (L-MSDAF), localized minimum sum of segment magnitudes of common edges (L-MSSM), and localized minimum sum of areas of child face (L-MSAF). Based on their effectiveness measurements in terms of form and size distortions, it is found that when two local regularities: L-MSDA and L-MSDSM are combined together, they can produce better performance. In addition, the best weightings for them to work together are identified as 10% for L-MSDSM and 90% for L-MSDA. The test results show that the combined usage of L-MSDA and L-MSDSM with identified weightings has a potential to be applied in other optimization based 3D recognition methods to improve their efficacy and robustness

Linking Sketching and Constraint Checking for Early Conceptual Design

At the start of the conceptual design process, designers start to give tangible form to their thoughts by sketching. This helps with reasoning and communicates ideas to other members of the team. Sketches are gradually worked up into more formal drawings which are then passed to the other stages of the design process. There are however some problems with basing early ideas on sketching. For example, due to their ad-hoc nature, sketches tend only to be diagrammatic representations and so designers cannot be sure that their ideas are feasible and what is being proposed meets the constraints described in the client brief. This can result in designers wasting time working up ideas which prove to be unsuitable. Also the process of constraint checking is complex and time consuming and so designers tend limit their search of possible options and instead choose satisfying rather than good solutions. This paper describes the INTEGRA project which examines the role of sketching in early conceptual design and how this can be linked to other aspects of the process and particularly automated constraint checking using an IT based approach. The focus for the work is the design of framed buildings. A multi-disciplinary approach has been adopted and the work has been undertaken in close collaboration with practising designers and clients

Interfaz gestual para la definición de condiciones de ensamblaje para la generación de maquetas digitales

[ESP] En el presente trabajo, se presenta un prototipo experimental denominado GEGROSS (GEsture & Geometric RecOnstruction based Sketch System) que pretende facilitar al máximo el proceso de ensamblaje de las piezas necesarias para crear una maqueta digital a través de la codificación mediante un lenguaje de gestos gráficos de las condiciones de ensamblaje. Para ello los elementos utilizados han sido por una parte el motor geométrico ACIS, el gestor de restricciones de ensamblaje 3D DCM de la firma D-Cubed, y la biblioteca CALI para la definición de interfaces gestuales. En el artículo se presenta la estrategia seguida para la integración de estas complejas herramientas, y el alfabeto de gestos desarrollado para las diferentes condiciones de ensamblaje.[ENG] In this paper we present an experimental prototype called GEGROSS (GEsture & eometric Reconstruction based Sketch System), that pretends to facility to the maximum the process of assembly in order to create a digital mock up, using the definition and codificationof graphical gestures of assembly condition. The elements used to make this possible have been: the geometric kernel ACIS, the constraint manager 3D DCM from D-Cubed firm and the CALI library for the definition of gestural interfaces. In this paper we present the strategy for the integration of these complex tools, and the gestural alphabet developed for the different assembly conditions.Este trabajo ha sido financiado por la Universidad de La Laguna a través del “Programa de Ayudas a la Investigación para la Formación y Promoción del Profesorado. Ayudas para Estancias de Investigadores Invitados” y por la Generalidad Valenciana, a través del proyecto de referencia CTIDIB/2002/51 de la convocatoria 2002 de Proyectos de I+D