IMPLEMENTATION AND UNIFORM MANAGEMENT OF MODELLING ENTITIES IN A MASSIVELY FEATURE-OBJECT ORIENTED ADVANCED CAD ENVIRONMENT

Today we are spectators of the transition process in computer aided design from traditional geometry based on design systems to advanced computer-based engineering systems. The key is the feature technology that allows both integrating and managing modelling entities in a coherent way. Feature technology is developing rapidly. New research topics and contexts are emerging from time to time. This paper introduces concept, design and technological feature-objects to support operational, structural and morphological modelling of mechanical products. First, the feature-centred approaches to conceptual design are summarized and evaluated. Then an implementation of concept feature-objects and the methodology for using them is presented. The strength of concept feature-objects is in their morphology inclusive nature. They appear as parametrized three-dimensional skeletons providing geometrical representations for the modelled engineering conceptions. A concept feature-object models the physical ports, contact surfaces related to ports, bones between ports, DOF of ports, relevant physical parameters, scientific and empirical descriptions of intentional transformations and environmental effects. Concept feature-objects are related to design feature-objects that, in turn, are constructed of a relevant set of technological feature-entities. Concept feature-objects refer to the configurable and parametrized design feature-objects through an indexing mechanism. The conceptions have been tested during the programming and further development of the authors' PRODES system

Novel affordances of computation to the design processes of kinetic structures

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1996.Includes bibliographical references (leaves 44-45).This paper is a discourse into the relationship between the process, computational tools and the role which symbolic structure can play in both. I argue the relationship of the process and tools is dialectic, whereby the tools we utilize in design develop new heuristics, the methodologies in tum, if reflectively understood, can be more aptly facilitated through the development of novel tools. The tools and the process then evolve together. A theory is laid out exploring the human visual information processing systems pertinence to the limitations in mental three-dimensional imaging and transformation operations relevant to the operations of drawing and mental visualization within the architectural design processes, substantiating the designers "necessity" to d raw (by traditional means, but more importantly here, through the inclusive integration of CAD within the process). The "necessity" to draw is explored as a re-presentational process to the visual system predicated upon the existence of a structured internal "library" of diagram-like representations. I argue that the ways we utilize such idiosyncratic libraries is predicated upon the ways in which we go about structuring the perceived "experienced" world around us into "symbol systems". And finally, the ways we utilize our reflective understanding of the heuristic transformations of these "symbols" within the design process in the context of a CAD environment are explored as a means to an enhanced understanding of that which is being designed and consequently as a vehicle for the development of future CAD systems to better facilitate such methodologies of designing. A personal design process of several kinetic structures is carried out in order to arrive at a localized process analysis within computer-aided design environment. Through an interactive, reflective process analysis, conclusions are drawn as to the affordances and limitations of such tools as suggestive of the operations a CAD environment might perform so as to better foster future methodologies of designing. The design "experiments" are utilized as a vehicle to understand the process. Specifically three kinetic projects are exploited for the prototypical "operations" they display. When difficulties or mental limitations are encountered with the operations, specific "tools" are developed to facilitate the limitation or to overcome the problem.by Michael A. Fox.M.S

VLSI Design

This book provides some recent advances in design nanometer VLSI chips. The selected topics try to present some open problems and challenges with important topics ranging from design tools, new post-silicon devices, GPU-based parallel computing, emerging 3D integration, and antenna design. The book consists of two parts, with chapters such as: VLSI design for multi-sensor smart systems on a chip, Three-dimensional integrated circuits design for thousand-core processors, Parallel symbolic analysis of large analog circuits on GPU platforms, Algorithms for CAD tools VLSI design, A multilevel memetic algorithm for large SAT-encoded problems, etc

A HOLISTIC APPROACH TO COMPUTER INTEGRATED MANUFACTURING ARCHITECTURE AND SYSTEMS DESIGN

This work addresses the problem of finding an improved solution to Computer Integrated Manufacturing (ClM) Architecture and Systems Design. The current approaches are shown to be difficult to understand and use, over complex. In spite of their complexity of approach they lack comprehensiveness and omit many factors and dimensions considered essential for success in today's competitive and often global market place. A new approach to ClM Architecture and Systems Design is presented which offers a simpler, more flexible and more robust format for defining a particular ClM System within a general architectural framework. At the same time this new approach is designed to offer a comprehensive and holistic solution. The research work involved the investigation of current approaches and research and development initiatives focusing particularly on the CIM-OSA and GRAI Integrated methodologies in the field of ClM Architecture. The strengths and weaknesses of the various approaches are examined. Developments in other related fields including manufacturing systems, manufacturing management, information technology and systems generally have been investigated regarding their relevance and possible contribution to an improved solution. The author has built on his practical experience in creating, designing and managing the implementation of a global CIM system. The authors work on several publicly funded collaborative research and development projects relevant to the problem area is described. These include CIM-OSA, IMOCIM and TIQS projects. In the latter two projects the author was instrumental in developing the methodological approach based on a systems approach to business processes in connection with the design of quality and manufacturing systems. Both of these projects have contributed to this work. The author has also participated in the global IMS programme as a rapporteur for the European Commission and this helped to provide a global perspective on the problems of manufacturing companies as they attempt to compete in a world wide market place. The results of this work provide the basis for a radically improved approach to ClM Architecture and Systems Design based on the holistic view of an enterprise. The approach developed supports the business process view of an enterprise; addresses the people and organisational aspects; leads to ClM solutions focused on meeting enterprise goals; and is able to deal with a significantly increased scope and complexity compared with existing methods yet is easily understood and more simple to simple to apply than current approaches

SUPPORTING FUNCTIONALITY-BASED DESIGN IN COMPUTER-AIDED DESIGN SYSTEMS

Designs are conceptualized in terms of the functions they need to accomplish. The need for a new product design arises as a result of the identification of a new functionality to be accomplished by the product. That is, design is functionality driven. However, existing CAD tools are not equipped to capture functionality or reason in such a fashion to support design for product functionality. This research proposes a new design formalism to enable functionality-driven design of mechanically engineered products. This procedure provides a methodology that allows a designer to model product functionality and to carry out conceptual design with the aid of a computer. It also serves as a bridging tool between the conceptual design phase and detailed design phase of a product. Thus, the primary objective of this research is to develop a methodology that will support the following activities in CAD systems: functionality modeling, functionality data structuring, and form conceptualization.The functionality modeling methodology developed in this work includes the use of operands, operators, and coupling bonds to describe product functionality in CAD systems. The Universal Modeling Language (an object-oriented programming technique) is used to model product functionality in computer systems. The tools developed in this research provide a means of modeling and propagating product functionality information to downstream design activities. The propagation of functionality as a constraint is achieved using Extensible Markup Language (XML) data files. These tools also provide a mechanism for verifying and enforcing constraints on solid CAD models. The functionality definition interface is implemented with a customized Microsoft Visio graphics engine.The tools developed in this research provide a means of modeling and propagating product functionality information to downstream design activities. It also provides a mechanism for verifying and enforcing constraints on solid CAD models. The functionality definition interface is implemented with a customized Microsoft Visio graphics engine

Tuotemallien tarkistuksen metriikan kehitys ja automaatio

A lot of interest and research has been focused on product quality and it is recognized as a crucial aspect of engineering. The quality of product models can also be seen as essential in engineering workflow especially in systems based on downstream data. Model quality effects not only the models accuracy and modifiability but also the agility of the whole engineering systems. Careful and thorough verification plays an important part in effecting product model quality. Verifying product models and designs manually can be laborious and time-consuming process. By automating parts of the verification process, benefits can be seen in the time frame and end results of the verification. The goal of the thesis is to develop metrics and automation for product model verification. Development of metrics is executed by researching literature for model quality metrics and construct a set of metrics for the company. Furthermore, the possibilities of product model verification automation are studied and a working automated model verification tool shall be created based on the metrics. The tool is intended be used in the current modeling environment. The outcomes of this thesis are a list of product quality dimensions with their corresponding metrics and a customized PTC ModelCHECK check that can automatically identify issues in product models. Quality dimensions were identified based on company needs and literature research. ModelCHECK platform was chosen for verification tool development as the software is readily available for the company which means it is a cost-effective way of utilizing automated product model verification in current design environment.Tuotteiden laatuun on jo pidemmän aikaa kiinnitetty paljon huomiota insinööriprosesseissa ja tutkimuksessa. Myös tuotemallien laatu voidaan nähdä insinöörityön kannalta elintärkeässä asemassa, erityisesti systeemeissä jotka perustuvat alaspäin virtaavaan tietoon. Mallien laatu vaikuttaa muun muassa sen tarkkuuteen ja muokattavuuteen sekä koko mallinnus- ja suunnittelujärjestelmän ketteryyteen. Huolellinen ja läpikotainen tarkistus on tärkeä osa tuotemallien laadun kehittämistä. Mallien manuaalinen tarkastaminen voi olla työlästä ja aikaavievää. Käyttämällä automaatiota tarkistuksen apuna, voidaan saavuttaa etuja tarkistuksen nopeudessa ja lopputuloksessa. Tämän diplomityön tavoitteena on kehittää tuotemallien tarkastuksen metriikkaa ja automaatiota. Metriikan kehitys perustuu kirjallisuustutkimukseen sekä muun muassa haastatteluissa kartoitettuihin yrityksen tarpeisiin. Tavoitteena on luoda tuotemalleille metriikkaa, joita vasten niiden ominaisuuksia voidaan arvioida. Myös tarkistuksen automaatiota tutkitaan ja tavoitteena on luoda automaattinen työkalu, jota voidaan käyttää yrityksen tämän hetkisessä suunnittelujärjestelmässä. Tutkimuksen lopputuloksena syntyi lista tuotemallien laadun ulottuvuuksista niihin liitetyillä metriikoilla ja metriikan mukainen PTC ModelCHECK tarkistuspohja 3D-malleille, joka löytyy automaattisesti virheitä malleista. ModelCHECK valittiin työkaluksi, koska se on valmiiksi saatavilla yrityksen nykyisessä mallinnusjärjestelmässä, joilloin automatisointi on erittäin kustannustehokasta

Virtual prototyping with surface reconstruction and freeform geometric modeling using level-set method

More and more products with complex geometries are being designed and manufactured by computer aided design (CAD) and rapid prototyping (RP) technologies. Freeform surface is a geometrical feature widely used in modern products like car bodies, airfoils and turbine blades as well as in aesthetic artifacts. How to efficiently design and generate digital prototypes with freeform surfaces is an important issue in CAD. This paper presents the development of a Virtual Sculpting system and addresses the issues of surface reconstruction from dexel data structures and freeform geometric modeling using the level-set method from distance field structure. Our virtual sculpting method is based on the metaphor of carving a solid block into a 3D freeform object using a 3D haptic input device integrated with the computer visualization. This dissertation presents the result of the study and consists primarily of four papers --Abstract, page iv

Embodied Interactions for Spatial Design Ideation: Symbolic, Geometric, and Tangible Approaches

Computer interfaces are evolving from mere aids for number crunching into active partners in creative processes such as art and design. This is, to a great extent, the result of mass availability of new interaction technology such as depth sensing, sensor integration in mobile devices, and increasing computational power. We are now witnessing the emergence of maker culture that can elevate art and design beyond the purview of enterprises and professionals such as trained engineers and artists. Materializing this transformation is not trivial; everyone has ideas but only a select few can bring them to reality. The challenge is the recognition and the subsequent interpretation of human actions into design intent

오프셋 곡선 및 곡면의 자가 교차 검출 및 제거

학위논문(박사)--서울대학교 대학원 :공과대학 컴퓨터공학부,2020. 2. 김명수.Offset curves and surfaces have many applications in computer-aided design and manufacturing, but the self-intersections and redundancies must be trimmed away for their practical use. We present a new method for offset curve and surface trimming that detects the self-intersections and eliminates the redundant parts of an offset curve and surface that are closer than the offset distance to the original curve and surface. We first propose an offset trimming method based on constructing geometric constraint equations. We formulate the constraint equations of the self-intersections of an offset curve and surface in the parameter domain of the original curve and surface. Numerical computations based on the regularity and intrinsic properties of the given input curve and surface is carried out to compute the solution of the constraint equations. The method deals with numerical instability around near-singular regions of an offset surface by using osculating tori that can be constructed in a highly stable way, i.e., by offsetting the osculating torii of the given input regular surface. We reveal the branching structure and the terminal points from the complete self-intersection curves of the offset surface. From the observation that the trimming method based on the multivariate equation solving is computationally expensive, we also propose an acceleration technique to trim an offset curve and surface. The alternative method constructs a bounding volume hierarchy specially designed to enclose the offset curve and surface and detects the self-collision of the bounding volumes instead. In the case of an offset surface, the thickness of the bounding volumes is indirectly determined based on the maximum deviations of the positions and the normals between the given input surface patches and their osculating tori. For further acceleration, the bounding volumes are pruned as much as possible during self-collision detection using various geometric constraints imposed on the offset surface. We demonstrate the effectiveness of the new trimming method using several non-trivial test examples of offset trimming. Lastly, we investigate the problem of computing the Voronoi diagram of a freeform surface using the offset trimming technique for surfaces. By trimming the offset surface with a gradually changing offset radius, we compute the boundary of the Voronoi cells that appear in the concave side of the given input surface. In particular, we interpret the singular and branching points of the self-intersection curves of the trimmed offset surfaces in terms of the boundary elements of the Voronoi diagram.오프셋 곡선 및 곡면은 computer-aided design (CAD)와 computer-aided manufacturing (CAM)에서 널리 이용되는 연산들 중 하나이다. 하지만 실용적인 활용을 위해서는 오프셋 곡선 및 곡면에서 생기는 자가 교차를 찾고 이를 기준으로 오프셋 곡선 및 곡면에서 원래의 곡선 및 곡면에 가까운 불필요한 영역을 제거하여야한다. 본 논문에서는 오프셋 곡선 및 곡면에서 생기는 자가 교차를 계산하고, 오프셋 곡선 및 곡면에서 생기는 불필요한 영역을 제거하는 알고리즘을 제안한다. 본 논문은 우선 오프셋 곡선 및 곡면의 자가 교차점들과 그 교차점들이 기인한 원래 곡선 및 곡면의 점들이 이루는 평면 이등변 삼각형 관계로부터 오프셋 곡선 및 곡면의 자가 교차점의 제약 조건을 만족시키는 방정식들을 세운다. 이 제약식들은 원래 곡선 및 곡면의 변수 공간에서 표현되며, 이 방정식들의 해는 다변수 방정식의 해를 구하는 solver를 이용하여 구한다. 오프셋 곡면의 경우, 원래 곡면의 주곡률 중 하나가 오프셋 반지름의 역수와 같을 때 오프셋 곡면의 법선이 정의가 되지 않는 특이점이 생기는데, 오프셋 곡면의 자가 교차 곡선이 이 부근을 지날 때는 자가 교차 곡선의 계산이 불안정해진다. 따라서 자가 교차 곡선이 오프셋 곡면의 특이점 부근을 지날 때는 오프셋 곡면을 접촉 토러스로 치환하여 더 안정된 방법으로 자가 교차 곡선을 구한다. 계산된 오프셋 곡면의 자가 교차 곡선으로부터 교차 곡선의 $xyz$-공간에서의 말단 점, 가지 구조 등을 밝힌다. 본 논문은 또한 바운딩 볼륨 기반의 오프셋 곡선 및 곡면의 자가 교차 곡선 검출을 가속화하는 방법을 제시한다. 바운딩 볼륨은 기저 곡선 및 곡면을 단순한 기하로 감싸고 기하 연산을 수행함으로써 가속화에 기여한다. 오프셋 곡면의 자가 교차 곡선을 구하기 위하여, 본 논문은 오프셋 곡면의 바운딩 볼륨 구조를 기저 곡면의 바운딩 볼륨과 기저 곡면의 법선 곡면의 바운딩 볼륨의 구조로부터 계산하며 이때 각 바운딩 볼륨의 두께를 계산한다. 또한, 바운딩 볼륨 중에서 실제 오프셋 곡선 및 곡면의 자가 교차에 기여하지 않는 부분을 깊은 재귀 전에 찾아서 제거하는 여러 조건들을 나열한다. 한편, 자가 교차가 제거된 오프셋 곡선 및 곡면은 기저 곡선 및 곡면의 보로노이 구조와 깊은 관련이 있는 것이 알려져 있다. 본 논문에서는 자유 곡면의 연속된 오프셋 곡면들로부터 자유 곡면의 보로노이 구조를 유추하는 방법을 제시한다. 특히, 오프셋 곡면의 자가 교차 곡선 상에서 나타나는 가지 점이나 말단 점과 같은 특이점들이 자유 곡면의 보로노이 구조에서 어떻게 해석되는지 제시한다.1. Introduction 1 1.1 Background and Motivation 1 1.2 Research Objectives and Approach 7 1.3 Contributions and Thesis Organization 11 2. Preliminaries 14 2.1 Curve and Surface Representation 14 2.1.1 Bezier Representation 14 2.1.2 B-spline Representation 17 2.2 Differential Geometry of Curves and Surfaces 19 2.2.1 Differential Geometry of Curves 19 2.2.2 Differential Geometry of Surfaces 21 3. Previous Work 23 3.1 Offset Curves 24 3.2 Offset Surfaces 27 3.3 Offset Curves on Surfaces 29 4. Trimming Offset Curve Self-intersections 32 4.1 Experimental Results 35 5. Trimming Offset Surface Self-intersections 38 5.1 Constraint Equations for Offset Self-Intersections 38 5.1.1 Coplanarity Constraint 39 5.1.2 Equi-angle Constraint 40 5.2 Removing Trivial Solutions 40 5.3 Removing Normal Flips 41 5.4 Multivariate Solver for Constraints 43 5.A Derivation of f(u,v) 46 5.B Relationship between f(u,v) and Curvatures 47 5.3 Trimming Offset Surfaces 50 5.4 Experimental Results 53 5.5 Summary 57 6. Acceleration of trimming offset curves and surfaces 62 6.1 Motivation 62 6.2 Basic Approach 67 6.3 Trimming an Offset Curve using the BVH 70 6.4 Trimming an Offset Surface using the BVH 75 6.4.1 Offset Surface BVH 75 6.4.2 Finding Self-intersections in Offset Surface Using BVH 87 6.4.3 Tracing Self-intersection Curves 98 6.5 Experimental Results 100 6.6 Summary 106 7. Application of Trimming Offset Surfaces: 3D Voronoi Diagram 107 7.1 Background 107 7.2 Approach 110 7.3 Experimental Results 112 7.4 Summary 114 8. Conclusion 119 Bibliography iDocto