A Method To Improve Matching Process by Shape Characteristics in Parametric Systems

10 pagesInternational audienceIn current parametric systems, the persistent naming issue (based on edge mappings of intersecting surfaces) is not as fully supported as it should be. Unpredictability and ambiguity of models often happen during design reevaluation within systems. This reference deficiency is widely treated in the literature, especially about non-planar entities during design construction. Although related works ensure the uniqueness of the references to topological entities, they often neglect the shape characteristics of surfaces and give results different from those expected during design reevaluation. We propose in this paper a method to add some additional information about surfaces to improve such works. We compute those information by decomposing surfaces according to hump(s) and/or hollow(s). More precisely, our method use local extremums and inflexion curves to obtain one hump or hollow per sub-surface. The existing matching processes replace every surface with their corresponding subsurfaces, leading to the right edge mappings

Feature-based Product Modelling in a Collaborative Environment

Ph.DDOCTOR OF PHILOSOPH

Parametric design velocity computation for CAD-based design optimization using adjoint methods

This paper presents an efficient optimization process, where the parameters defining the features in a feature-based CAD model are used as design variables. The process exploits adjoint methods for the computation of gradients, and as such the computational cost is essentially independent of the number of design variables, making it ideal for optimization in large design spaces. The novelty of this paper lies in linking the adjoint surface sensitivity information with geometric sensitivity values, referred to as design velocities, computed for CAD models created in commercial CAD systems (e.g. CATIA V5 or Siemens NX)

Constraint-Enabled Design Information Representation for Mechanical Products Over the Internet

Global economy has made manufacturing industry become more distributed than ever before. Product design requires more involvement from various technical disciplines at different locations. In such a geographically and temporally distributed environment, efficient and effective collaboration on design is vital to maintain product quality and organizational competency. Interoperability of design information is one of major barriers for collaborative design. Current standard CAD data formats do not support design collaboration effectively in terms of design information and knowledge capturing, exchange, and integration within the design cycle. Multidisciplinary design constraints cannot be represented and transferred among different groups, and design information cannot be integrated efficiently within a distributed environment. Uncertainty of specification cannot be modeled at early design stages, while constraints for optimization are not embedded in design data. In this work, a design information model, Universal Linkage model, is developed to represent design related information for mechanical products in a distributed form. It incorporates geometric and non-geometric constraints with traditional geometry and topology elements, thus allows more design knowledge sharing in collaborative design. Segments of design data are linked and integrated into a complete product model, thus support lean design information capturing, storage, and query. The model is represented by Directed Hyper Graph and Product Markup Language to preserve extensibility and openness. Incorporating robustness consideration, an Interval Geometric Modeling scheme is presented, in which numerical parameters are represented by interval values. This scheme is able to capture uncertainty and inexactness of design and reduces the chances of conflict in constraint imposition. It provides a unified constraint representation for the process of conceptual design, detailed design, and design optimization. Corresponding interval constraint solving methods are studied

ATLAS, a platform for distributed graphics applications

ATLAS, a platform for developing distributed applications by splitting them into several collaborating processes scattered in a local area network is presented. Although of general use, it has features especially designed for supporting graphics applications. We present its architecture and some aspects of its implementation, and discuss design criteria.Postprint (author’s final draft

A Generic Parametric Modeling Engine Targeted Towards Multidisciplinary Design: Goals and Concepts

This paper presents the design concept of a generic parametric modeling engine that is completely decoupled from geometry generation. Driven by requirements extracted from preliminary multidisciplinary airplane design, the presented software architecture provides a platform that enables an interplay of different modeling and simulation tools on the one hand, and their efficient execution in a parametric tree on the other hand. An integrated plugin system allows users to define custom plugins exposing arbitrary types and functions. All geometric functionality is provided via plugins, decoupling it entirely from the parametric engine. First, we specify the goals that the software framework needs to fulfill, elaborating on the requirements encountered in early aircraft design. Then, we describe the software architecture and its modules, realized as a C++ library. As such, the software is a back-end that can be used by third party developers to create user-friendly and interoperable tools. The core of the framework is a parametric engine called grunk with its integrated plugin system and serialization functionality. The key feature of grunk is the possibility for users to define custom types in plugins and their use in the parametric tree. Geometric modeling functionalities are provided through the plugins grocc and geo: the first integrating OpenCascade Technology's functionalities and the latter extending it. A major feature on the geometry side is the provision of derivatives through algorithmic differentiation, making the framework particularly suitable for gradient-based optimization applications. Finally, we demonstrate the use of the software via examples and show the results

Quality management approach of product data models for shipbuilding

A quality management approach to manage the quality of ship product model data is discussed. It aims to improve and to automate product data model control to make the design and production processes more reliable. This approach is supporting an efficient correction of decient structural designs under visual guidance towards the identied problems. Two international standards ISO STEP-59 and ISO/PAS 26183:2006 are utilized in this thesis

3D Mass Customization Toolkits Design, Part I: Survey and an Evaluation Model

Mass customization (MC) allows consumers to design their own products or services through online MC toolkits. The application of geometric modeling through modern web-browsers allows for the presentation of a virtual 3D product, resulting in a number of commercial 3D MC sites. To gain a deeper understanding of the toolkits that drive these sites, this article provides a comprehensive investigation into web-based toolkit design. Based on this review, an evaluation model for 3D MC toolkits is proposed that considers four aspects: Individual Differences, Solution Space, Interaction Design and Enabling Technologies. This leads to a follow-up article that applies the 3D toolkit evaluation model to assess commercial 3D toolkits which are available on the current market