Cumincad : CUMINCAD Papers : Search Results

CumInCAD is a Cumulative Index about publications in Computer Aided Architectural Design
supported by the sibling associations ACADIA, CAADRIA, eCAADe, SIGraDi, ASCAAD and CAAD futures

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_id	a6f1
authors	Bridges, A.H.
year	1986
title	Any Progress in Systematic Design?
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 5-15
summary	In order to discuss this question it is necessary to reflect awhile on design methods in general. The usual categorization discusses 'generations' of design methods, but Levy (1981) proposes an alternative approach. He identifies five paradigm shifts during the course of the twentieth century which have influenced design methods debate. The first paradigm shift was achieved by 1920, when concern with industrial arts could be seen to have replaced concern with craftsmanship. The second shift, occurring in the early 1930s, resulted in the conception of a design profession. The third happened in the 1950s, when the design methods debate emerged; the fourth took place around 1970 and saw the establishment of 'design research'. Now, in the 1980s, we are going through the fifth paradigm shift, associated with the adoption of a holistic approach to design theory and with the emergence of the concept of design ideology. A major point in Levy's paper was the observation that most of these paradigm shifts were associated with radical social reforms or political upheavals. For instance, we may associate concern about public participation with the 1970s shift and the possible use (or misuse) of knowledge, information and power with the 1980s shift. What has emerged, however, from the work of colleagues engaged since the 1970s in attempting to underpin the practice of design with a coherent body of design theory is increasing evidence of the fundamental nature of a person's engagement with the design activity. This includes evidence of the existence of two distinctive modes of thought, one of which can be described as cognitive modelling and the other which can be described as rational thinking. Cognitive modelling is imagining, seeing in the mind's eye. Rational thinking is linguistic thinking, engaging in a form of internal debate. Cognitive modelling is externalized through action, and through the construction of external representations, especially drawings. Rational thinking is externalized through verbal language and, more formally, through mathematical and scientific notations. Cognitive modelling is analogic, presentational, holistic, integrative and based upon pattern recognition and pattern manipulation. Rational thinking is digital, sequential, analytical, explicatory and based upon categorization and logical inference. There is some relationship between the evidence for two distinctive modes of thought and the evidence of specialization in cerebral hemispheres (Cross, 1984). Design methods have tended to focus upon the rational aspects of design and have, therefore, neglected the cognitive aspects. By recognizing that there are peculiar 'designerly' ways of thinking combining both types of thought process used to perceive, construct and comprehend design representations mentally and then transform them into an external manifestation current work in design theory is promising at last to have some relevance to design practice.
series	CAAD Futures
email
last changed	2003/11/21 15:16

_id	f5db
authors	Brooks, F.P.
year	1986
title	Walkthrough - A Dynamic Graphics System for Simulating Virtual Buildings
source	Proceedings 1986 Workshop on Interactive 3D Graphics. ACM: 9-22
summary	As part of our graphics research into virtual worlds, we are building a tool for an architect and his client to use for rapid prototyping of buildings by visually "walking through" them in order to refine specifications. Our first prototype simulated the new UNC Computer Science building with some 8000 polygons. BSP-tree software on the Adage Ikonas gave a colored, shaded perspective view every 3-5 seconds while the user moved a cursor in real-time over floorplans shown on the Vector-General 3300. The current (third) version uses Pixel-Planes to generate 9 updates/second, view images shown 4' x 6' by projector. Active short- and long-term research questions include speed-up, stereo, a 6-DoF interface with eye-level defaults, and an interactive model-building, model-changing system.
series	other
last changed	2003/11/21 15:16

_id	0354
authors	Goodman, Gary and Reddy, Raj D.
year	1978
title	Alternative Control Structures for Speech Understanding Systems
source	1978 ? [13] p. : ill. includes bibliography Control structures are an essential part of any speech recognition system. They are the devices by which passive knowledge about the task and language is transformed into active and effective processes. In the chapter, three areas of control structures are defined and discussed: knowledge source interaction, knowledge source activation, and knowledge source focusing. Discussion relates the concepts presented to systems developed during the five-year ARPA speech understanding project. speech recognition / systems / control / structures / AI. 64. Goodman, Tim and Keith Unsworth. 'Manipulating Shape and Producing Geometric Continuity in B-spline Curves.' IEEE Computer Graphics and Applications. February, 1986. vol. 6: pp. 50-56 : ill. includes bibliography.
summary	This article examines some of the desirable features of B- splines that make them particularly suitable for computer- aided design. First, a theoretical analysis is presented regarding the effects upon the shape of a design curve when the bias and tension parameters are allowed to vary in certain ways. Second, the concept of geometric continuity is discussed, and conditions are derived upon the control vertices to ensure that the design curve has second-order geometric continuity. Illustrations of B-spline curves are presented to support the theoretical conclusions
keywords	computational geometry, B-splines, curves, CAD
series	CADline
last changed	2003/06/02 13:58

_id	29c2
authors	Ozel, Filiz
year	1991
title	An Intelligent Simulation Approach in Simulating Dynamic Processes in Architectural Environments
source	Computer Aided Architectural Design Futures: Education, Research, Applications [CAAD Futures ‘91 Conference Proceedings / ISBN 3-528-08821-4] Zürich (Switzerland), July 1991, pp. 177-190
summary	The implications of object-oriented data models and rule-based reasoning systems is being researched in a wide variety of application areas ranging from VLSI circuit design (Afsannanesh et al 1990) to architectural environments (Coyne et al 1990). The potential of this approach in the development of discrete event simulations is also being scrutinized (Birtwistle et al 1986). Such computer models are usually called "expert simulations" or "intelligent simulations". Typically rule-basing in such models allows the definition of intelligent-objects that can reason about the simulated dynamic processes through an inferencing system. The major advantage of this approach over traditional simulation languages is its ability to provide direct reference to real world objects and processes. The simulation of dynamic processes in architectural environments poses an additional Problem of resolving the interaction of architectural objects with other objects such as humans, water, smoke etc., depending on the process simulated. Object-oriented approach promises potential in solving this specific problem. The first part of this paper addresses expert simulation approach within the context of architectural settings, then the second part summarizes work done in the application of such an approach to an emergency egress simulation.
series	CAAD Futures
last changed	1999/04/07 12:03

_id	02c6
authors	Wheeler, B.J.Q
year	1986
title	A Unified Model for Building
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 200-231
summary	It is commonly recognized that the time-honoured procedure for preparing an architectural design for building on site is inefficient. Each member of a team of consultant professionals makes an independently documented contribution. For a typical project involving an architect and structural, electrical, mechanical and public services engineers there will be at least five separate sets of general- arrangement drawings, each forming a model of the building, primarily illustrating one discipline but often having to include elements of others in order to make the drawing readable. For example, an air-conditioning duct-work layout is more easily understood when superimposed on the room layout it serves which the engineer is not responsible for but has to understand. Both during their parallel evolution and later, when changes have to be made during the detailed design and production drawing stages, it is difficult and time consuming to keep all versions coordinated. Complete coordination is rarely achieved in time, and conflicts between one discipline and another have to be rectified when encountered on site with resulting contractual implications. Add the interior designer, the landscape architect and other specialized consultants at one end of the list and contractors' shop drawings relating to the work of all the consultants at the other, and the number of different versions of the same thing grows, escalating the concomitant task of coordination. The potential for disputes over what is the current status of the design is enormous, first, amongst the consultants and second, between the consultants and the contractor. When amendments are made by one party, delay and confusion tend to follow during the period it takes the other parties to update their versions to include them. The idea of solving this problem by using a common computer-based model which all members of the project team can directly contribute to is surely a universally assumed goal amongst all those involved in computer-aided building production. The architect produces a root drawing or model, the 'Architect's base plan', to which the other consultants have read-only access and on top of which they can add their own write-protected files. Every time they access the model to write in the outcome of their work on the project they see the current version of the 'Architect's base plan' and can thus respond immediately to recent changes and avoid wasting time on redundant work. The architect meanwhile adds uniquely architectural material in his own overlaid files and maintains the root model as everybody's work requires. The traditional working pattern is maintained while all the participants have the ability to see their colleagues, work but only make changes to those parts for which they are responsible.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	ddss9846
id	ddss9846
authors	Rigatti, Decio
year	1998
title	Rubem Berta Housing Estate: Order and Structure, Designand Use
source	Timmermans, Harry (Ed.), Fourth Design and Decision Support Systems in Architecture and Urban Planning Maastricht, the Netherlands), ISBN 90-6814-081-7, July 26-29, 1998
summary	The main goal of this paper is to investigate, through some space configurational based tools, a quite common phenomenon found in many different locations in Brazil, concerning the process of urban changes individually introduced by dwellers of public housing estates. A significant number of housing estates, particularly those designed according to rationalist concepts, seem to be unable to support space related social requirements and are then widely transformed when compared to the original layouts. Beyond the quantitative features, the morphological changes that take place in those housing estates mean a fundamental new approach to understand how completely new urban structures can arisefrom the space produced by a comprehensive urban design, took as a starting point for the transformations made by the dwellers of those settlements. As a case study is analysed the Rubem Berta Housing Estate which was built in Porto Alegre/RS, Brazil, for 20,000 people in the late 70’s. Since the begining of its occupation in 1986 and the invasion that took place in 1987, the urban transformations there have never stopped. It’s possible to realize that the dwellers individually use some constant physical rules to define the new settlement which are very similar within the estate itself and, at the same time, very similar to those found in other transformed housing estates of this sort. The physical rules introduced change the features of the entire settlement in two different levels: a) locally, through the transformations introduced in order to solve individual needs; b) globally, the local rules of physical transformations produce a new overall structure for the whole urban complex. The knowledge of this process makes it possible to bring to the surface of architectural theory some generic configurational codes that can be used as a tool for designing public housing estates in Brazil.
series	DDSS
last changed	2003/08/07 16:36

_id	ad96
authors	Gudes, Ehud and Bracha, Gilad
year	1986
title	GCI : A Tool for Developing Interactive CAD User Interfaces
source	26 p. : ill. Israel: 1986? includes bibliography
summary	GCI is a Unix based tool for developing interactive CAD programs. By separating command/menu definitions from the program, GCI makes it easier to change and extend the user interface. The language provided by GCI is used to define syntax of commands, menus, messages, and help text. Generally, GCI supports a static hierarchical structure of commands and menus. However, through a program interface, an application program has the freedom to change environments, commands and menus. This flexibility of run-time control of the user interface is essential for developing highly responsive interfaces in a CAD environment. This paper presents the main concepts and definition language of GCI. It then discusses architectural and implementation issues, and finally presents a typical application's view of using the tool
keywords	user interface, design, management, systems, tools, CAD
series	CADline
last changed	2003/06/02 10:24

_id	079f
authors	Dickson, Gary W., DeSanctis, Gerardine and McBride, D. J.
year	1986
title	Understanding the Effectiveness of Computer Graphics for Decision Support : A Cumulative Experimental Approach
source	Communications of the ACM. January, 1986. vol. 29: pp. 40-47. includes bibliography
summary	A total of 840 junior and senior-level undergraduate business students participated in three experiments that compared computer-generated graphical forms of data presentation to traditional tabular reports. The first experiment compared tables and bar charts for their effects on readability, interpretation accuracy, and decision making. No differences in interpretation accuracy or decision quality were observed for the two groups, although tabular reports were rated as 'easier to read and understand' than graphical reports. The second experiment compared line plots to tables for their effects on interpretation accuracy and decision quality. Subjects with graphical reports outperformed those with tables. There were no meaningful differences in interpretation accuracy across treatment groups. The third experiment compared graphical and tabular reports for their ability to convey a 'message' to the reader. Only in situations in which a vast amount of information was presented and relatively simple impressions were to be made, did subjects given graphs outperform those using tables. This program of cumulative experiments indicates that generalized claims of superiority of graphic presentation are unsupported, at least for decision-related activities. In fact, the experiments suggest that the effectiveness of the data display format is largely a function of the characteristics of the task at hand, and that impressions gleaned from 'one shot' studies of the effectiveness of the use of graphs may be nothing more than situationally dependent artifacts
keywords	business, computer graphics, presentation, decision making, visualization
series	CADline
last changed	2003/06/02 13:58

_id	578f
id	578f
authors	Flemming, Ulrich and Schmitt, Gerhard
year	1986
title	The Computer in the Design Studio. Ideas and Exercises that Go Beyond Automated Drafting
doi	https://doi.org/10.52842/conf.acadia.1986.055
source	ACADIA Workshop ‘86 Proceedings - Houston (Texas - USA) 24-26 October 1986, pp. 55-78
summary	The present use of computers in the design studio focusses on automating routine tasks and on increasing drawing productivity. We assume that the impact of computers in design can be more profound and present a series of exercises for two contrasting design studios that build on our teaching and computing experience. 'Me first studio uses the computer as a design evaluation tool. The second studio demonstrates the use of computers for simple design generation tasks. In both cases, a very general and important educational objective is pursued, and computers become an integral part of the exercise.
series	ACADIA
email
last changed	2022/06/07 07:51

_id	40fe
authors	Gero, John S., Oxman, Rivka E. and Manago, C.
year	1986
title	Graphics and Expert Systems
source	AUSGRAPH '86 Australian Conference on Computer Graphics (4th : 1986 : Sydney). pp. 25-29 : ill. includes bibliography
summary	Expert systems are a novel software technology which aim to model the behavior and knowledge of human experts. This paper presents two modes of interaction between graphics and expert systems in the domain of computer-aided design. The first concerns the interaction between an expert system and commercial CAD systems. The second demonstrates how expert systems can control design oriented graphical representations. Examples from both modes are presented from systems developed at Sydney University
keywords	computer graphics, expert systems, CAD, architecture
series	CADline
email
last changed	2003/06/02 10:24

_id	cc1a
authors	Lien, Kristian, Go Suzuki and Westerberg, Arthur W.
year	1986
title	The Role of Expert Systems Technology In Design
source	[2] 49 p. : diagrams Engineering Design Research Center, CMU, September, 1986 EDRC-06-13-86. includes bibliography.
summary	Using a scenario format, this paper first reviews the nature of chemical process design, showing that designers quickly make major decisions with minimal information and constantly revise their strategy to solve a problem. To automate this activity on a computer will require models of the process being created at several levels of abstraction as well as models that capture the beliefs of the modeler about the abilities of himself, others and the aids available and models of strategies for complex problem solving. The second section of the paper extensively reviews current expert system concepts, illustrating each of them with design examples. It is argued that expert systems are knowledge based. The authors describe many of the control strategies used in today's systems, and also consider different problem representations - rules, logic and frames - and indicate when each might be preferred. The last section presents the authors views on what will be involved in creating a future expert system for design
keywords	engineering, abstraction, expert systems, CAD, design process, representation, knowledge base, frames, control
series	CADline
last changed	2003/06/02 10:24

_id	ac2c
authors	Panunzi, Stefano and Sansoni, Claudio
year	1986
title	Transformations of the Shanberg House - Analysis of a Plan and Planning Experimentations, Using the Instruments of Multicriterial Analysis as Means of Research.
doi	https://doi.org/10.52842/conf.ecaade.1986.097
source	Teaching and Research Experience with CAAD [4th eCAADe Conference Proceedings] Rome (Italy) 11-13 September 1986, pp. 97-110
summary	During the last years some research programs have been developed aiming to analyse a particular architectonic language, using mathematical and informatic instruments. Some of these research programs have as second aim the making of a method for creating a geometrical planning-language: most of these studies are dedicated to the research into the laws which rule the personal style used by an author in certain works. Instead, this research program aims to analyse the planning process, not from the point of view of those who want to reconstruct the laws which describe the stile of a particular author but, by trying to understand the “compositive” process, analysing it by reconstructing the project itself, through a dynamic aggregative process of subsequent parts.
series	eCAADe
email
last changed	2022/06/07 08:00

_id	44fe
authors	Ramaekers, J.M.A.
year	1986
title	Experiences with CAD at the Hogere Technische School te Heerlen
doi	https://doi.org/10.52842/conf.ecaade.1986.121
source	Teaching and Research Experience with CAAD [4th eCAADe Conference Proceedings] Rome (Italy) 11-13 September 1986, pp. 121-126
summary	In comparison with the educational institutions abroad, the Hogere Technische School can be translated with "Higher Technical School". In Germany it would be"Fachhochschule" The highest level of education at'- the HTS is similar to the level in the second year of the university. Contrary the university study, the study at the HTS is directed at the professional practice. The HTS is national well-known because of her education in CAD-instructions. at the moment CAD-instruction is best developed at the department of building engineering.
series	eCAADe
last changed	2022/06/07 08:00

_id	a980
authors	Rosenman, Michael A., Gero, John S. and Hutchinson, Peter J. (et al)
year	1986
title	Expert Systems Applications in Computer-aided Design
source	Guildford: Butterworth, 1986. pp. 218-225. Reprinted in Computer Aided Design 18(10): pp. 546-551
summary	Rule-based expert system shells are demonstrated to be useful in elementary design decision making. Two applications are presented which utilize the BUILD shell. The first is concerned with the selection and design of earth-retaining structures and makes use of passive graphics in descriptions. The second is concerned with the analysis and synthesis of kitchens and uses graphics to allow the user to interact with the system. Such systems are useful when the range of options is small
keywords	applications, CAD, expert systems, design process, architecture
series	CADline
email
last changed	2003/06/02 13:58

_id	2b17
authors	Salesin, David and Barzel, Ronen
year	1986
title	Two-Bit Graphics
source	IEEE Computer Graphics and Applications. June, 1986. vol. 6: pp. 36-42 : ill. includes bibliography
summary	Ordinary bitmaps allow pixels to be black or white. The authors introduce a second bitmap, the 'alpha' bitmap, which allows pixels to be transparent as well. The alpha bitmap makes it possible to have black-and-white images that are nonrectangular or that have holes in them. It also provides a richer set of operations for working with bitmaps. The article presents the mathematics for a two-bit compositing algebra, and suggest extensions for two-bit compositing, painting, and region filling. Each of these operations can be implemented with ordinary bitbits and presented on ordinary bitmap displays. The authors analyze the cost of each two-bit operation in terms of the number of bitbits it requires
keywords	computer graphics, algorithms, display
series	CADline
last changed	2003/06/02 13:58

_id	020d
authors	Shaviv, Edna
year	1986
title	Layout Design Problems: Systematic Approaches
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 28-52
summary	The complexity of the layout design problems known as the 'spatial allocation problems' gave rise to several approaches, which can be generally classified into two main streams. The first attempts to use the computer to generate solutions of the building layout, while in the second, computers are used only to evaluate manually generated solutions. In both classes the generation or evaluation of the layout are performed systematically. Computer algorithms for 'spatial allocation problems' first appeared more than twenty-five years ago (Koopmans, 1957). From 1957 to 1970 over thirty different programs were developed for generating the floor plan layout automatically, as is summarized in CAP-Computer Architecture Program, Vol. 2 (Stewart et al., 1970). It seems that any architect who entered the area of CAAD felt that it was his responsibility to find a solution to this prime architectural problem. Most of the programs were developed for batch processing, and were run on a mainframe without any sophisticated input/output devices. It is interesting to mention that, because of the lack of these sophisticated input/output devices, early researchers used the approach of automatic generation of optimal or quasioptimal layout solution under given constraints. Gradually, we find a recession and slowdown in the development of computer programs for generation of layout solutions. With the improvement of interactive input/output devices and user interfaces, the inclination today is to develop integrated systems in which the architectural solution is obtained manually by the architect and is introduced to the computer for the appraisal of the designer's layout solution (Maver, 1977). The manmachine integrative systems could work well, but it seems that in most of the integrated systems today, and in the commercial ones in particular, there is no route to any appraisal technique of the layout problem. Without any evaluation techniques in commercial integrated systems it seems that the geometrical database exists Just to create working drawings and sometimes also perspectives.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	a230
authors	Stazi, A., Munafo, P. and Giampieri, O.
year	1986
title	Proceedings Relative to a Quick Determination of Thermal Performances of Passive Solar Systems
doi	https://doi.org/10.52842/conf.ecaade.1986.305
source	Teaching and Research Experience with CAAD [4th eCAADe Conference Proceedings] Rome (Italy) 11-13 September 1986, pp. 305-322
summary	In the following report it's reported on a research still going on, which aims at establishing easy to use computing methods to allow to quickly compute the thermal loads at first stage of approximation and the performances of the most significant solar systems, which can be applied private. The research is developing through three steps. In the first step the research team recognised the most and housings occurring in residence building. In the second step, also with regard to the outcomes of the theoretical reference model has been loads and the performances of the passive solar systems have been computed for, when varying a few parameters regarding building typology, alignment of the body of the building, flats layout, walls shape, and so on. In the third step the interval range, where the model can fit into, and the correcting coefficients are set through theoretical and experimental tests.
series	eCAADe
last changed	2022/06/07 07:56

_id	f3aa
authors	Tyler, Sherman William
year	1986
title	SAUCI. Self-Adaptive User Computer Interfaces
source	Carnegie Mellon University,Pittsburgh
summary	Different approaches to the design of the human-computer interface have been taken in the past. These can be organized into four broad categories: tack-on; intuitive/empirical; formal; and conversational. There are several important interface design criteria that have never been adequately attained in any of these approaches. One is modularity, that is, maintaining a clear separation between the interface and its target system. A second criterion is self-adaptation, or the ability of the interface to modify its own behavior to suit a given individual user. Two further criteria relate to the interface's potential to guide users in performing typical high-level tasks on the target system and to provide intelligent advice on the use of that system. This research was focused on developing an integrated technique for achieving these four design criteria. To that end, an abstract architecture called SAUCI, or the Self-Adaptive User-Computer Interface, was proposed, embodying a knowledge-based, object-oriented approach to interface design. The foundation of this approach rests upon information encoded within sets of objects. This information includes separate knowledge bases describing the individual users, the commands of the target system, and the high-level tasks appropriate for that system. The behavior of the interface is controlled by various methods which call upon the knowledge bases in a rule-governed manner to decide what interface features should be present at each phase of the user's dialogue with the target system. To test the feasibility of the proposed architecture, a working interface was implemented on a Xerox 1108 computer in the LOOPS language, with a UNIX operating system running on a separate minicomputer as the target system. An empirical evaluation of this prototype revealed clear advantages over the standard interface. Closer examination pointed to each of the factors of modularity, task guidance, and user-tailored assistance as playing a significant role in these effects. A discussion of additional applications of this architecture and of areas for future development is offered as further evidence of the value of this approach as a general framework for human-computer interface design.
series	thesis:PhD
last changed	2003/02/12 22:37

_id	452c
authors	Vanier, D. J. and Worling, Jamie
year	1986
title	Three-dimensional Visualization: A Case Study
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 92-102
summary	Three-dimensional computer visualization has intrigued both building designers and computer scientists for decades. Research and conference papers present an extensive list of existing and potential uses for threedimensional geometric data for the building industry (Baer et al., 1979). Early studies on visualization include urban planning (Rogers, 1980), treeshading simulation (Schiler and Greenberg, 1980), sun studies (Anon, 1984), finite element analysis (Proulx, 1983), and facade texture rendering (Nizzolese, 1980). With the advent of better interfaces, faster computer processing speeds and better application packages, there had been interest on the part of both researchers and practitioners in three-dimensional -models for energy analysis (Pittman and Greenberg, 1980), modelling with transparencies (Hebert, 1982), super-realistic rendering (Greenberg, 1984), visual impact (Bridges, 1983), interference clash checking (Trickett, 1980), and complex object visualization (Haward, 1984). The Division of Building Research is currently investigating the application of geometric modelling in the building delivery process using sophisticated software (Evans, 1985). The first stage of the project (Vanier, 1985), a feasibility study, deals with the aesthetics of the mode. It identifies two significant requirements for geometric modelling systems: the need for a comprehensive data structure and the requirement for realistic accuracies and tolerances. This chapter presents the results of the second phase of this geometric modelling project, which is the construction of 'working' and 'presentation' models for a building.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	47c5
authors	Weiler, Kevin J.
year	1986
title	Topological Structures for Geometric Modeling
source	Computer and Systems Engineering, Rensselaer Polytechnic Institute
summary	Geometric modeling technology for representing three-dimensional objects has progressed from early wireframe representations, through surface representations, to the most recent representation, solid modeling. Each of these forms has many possible representations. The boundary representation technique, where the surfaces, edges, and vertices of objects are represented explicitly, has found particularly wide application. Many of the more sophisticated versions of boundary representations explicitly store topological information about the positional relationships among surfaces, edges, and vertices. This thesis places emphasis on the use of topological information about the shape being modeled to provide a framework for geometric modeling boundary representations and their implementations, while placing little constraint on the actual geometric surface representations used. The major thrusts of the thesis fall into two areas of geometric modeling. First, a theoretical basis for two-manifold solid modeling boundary topology representation is developed. The minimum theoretical and minimum practical topological adjacency information required for the unambiguous topological representation of manifold solid objects is determined. This provides a basis for checking the correctness of existing and proposed representations. The correctness of the winged edge structure is also explored, and several new representations which have advantages over existing techniques are described and their sufficiency verified. Second, a non-two-manifold boundary geometric modeling topology representation is developed which allows the unified and simultaneous representation of wireframe, surface, and solid modeling forms, while featuring a representable range beyond what is achievable in any of the previous modeling forms. In addition to exterior surface features, interior features can be modeled, and non-manifold features can be represented directly. A new data structure, the Radial Edge structure, which provides access to all topological adjacencies in a non-manifold boundary representation, is described and its completeness is verified. A general set of non-manifold topology manipulation operators is also described which is independent of a specific data structure and is useful for insulating higher levels of geometric modeling functionality from the specifics and complexities of underlying data structures. The coordination of geometric and topological information in a geometric modeling system is also discussed.
series	thesis:MSc
last changed	2003/02/12 22:37

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