92 research outputs found
Feature technology - an overview
Manufacture is an objective that has become more urgent within the wider context of a total
Computer Integrated Manufacturing environment. In seeking this integration it is recognised
that the diversity of activities and consequent needs for data can best be served by a single
representation for design, design analysis and manufacturing planning, and that a strong
candidate for this descriptive role is a Feature Representation. This paper briefly overviews
the primary methods of the use of features through Feature Recognition and Design by
Features, particularly in the process planning application area
Feature technology : an overview
The proper integration of the activities of computer-aided design (CAD) and computer-aided manufacture (CAM)is an objective that has become more urgent within the wider context of a total computer integrated manufacturing (CIM) environment. In seeking this integration it is recognized that the diversity of activities and consequent needs for data can best be served by a single representation for design, design analysis and manufacturing planning, and that a strong candidate for this descriptive role is a feature representation. This paper briefly overviews the primary methods of the use of features through feature recognition and design by features, particularly in the process planning application area
Process capability modelling: a review report of feature representation methodologies
Approximately 150 technical papers on the features methodology have been carefully studied and some selected
papers have been commented upon. The abstracts of the comments are documented and attached to this report. The
methodologies reviewed are mainly divided into two approaches, ie. feature recognition and design by features.
Papers which deal with some specific topics such as feature taxonomies, dimensions and tolerances, feature
concepts, etc. are also included in the document
Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review
Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed
BREP Identification During Voxel-Based Collision Detection for Haptic Manual Assembly
This paper presents a novel method to tie geometric boundary representation (BREP) to voxel-based collision detection for use in haptic manual assembly simulation. Virtual Reality, in particular haptics, has been applied with promising results to improve preliminary product design, assembly prototyping and maintenance operations. However, current methodologies do not provide support for low clearance assembly tasks, reducing the applicability of haptics to a small subset of potential situations. This paper discusses a new approach, which combines highly accurate CAD geometry (boundary representation) with voxel models to support a hybrid method involving both geometric constraint enforcement and voxel-based collision detection to provide stable haptic force feedback. With the methods presented here, BREP data can be accessed during voxel-based collision detection. This information can be used for constraint recognition and lead to constraint-guidance during the assembly process
Hybrid modelling of time-variant heterogeneous objects.
The physical world consists of a wide range of objects of a diverse constitution. Past research was mainly focussed on the modelling of simple homogeneous objects of a uniform constitution. Such research resulted in the development of a number of advanced theoretical concepts and practical techniques for describing such physical objects. As a result, the process of modelling and animating certain types of homogeneous objects became feasible. In fact most physical objects are not homogeneous but heterogeneous in
their constitution and it is thus important that one is able to deal with such heterogeneous objects that are composed of diverse materials and may have complex internal structures. Heterogeneous object modelling is still a very
new and evolving research area, which is likely to prove useful in a wide range of application areas. Despite its great promise, heterogeneous object modelling is still at an embryonic state of development and there is a dearth
of extant tools that would allow one to work with static and dynamic heterogeneous objects. In addition, the heterogeneous nature of the modelled objects makes it appealing to employ a combination of different representations resulting in the creation of hybrid models.
In this thesis we present a new dynamic Implicit Complexes (IC) framework incorporating a number of existing representations and animation techniques. This framework can be used for the modelling of dynamic multidimensional
heterogeneous objects. We then introduce an Implicit Complexes Application Programming Interface (IC API). This IC API is designed to provide various applications with a unified set of tools allowing these to model time-variant heterogeneous objects. We also present a new Function Representation (FRep) API, which is used for the integration of FReps into complex time-variant hybrid models. This approach allows us to create a practical
multilevel modelling system suited for complex multidimensional hybrid modelling of dynamic heterogeneous objects. We demonstrate the advantages of our approach through the introduction of a novel set of tools tailored
to problems encountered in simulation applications, computer animation and computer games. These new tools empower users and amplify their creativity by allowing them to overcome a large number of extant modelling and animation
problems, which were previously considered difficult or even impossible to solve
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