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	56af
authors	Nakamae, E., Takao, I., Nishita, T. and Takita, S.
year	1989
title	Compositing 3D Images with Antialiasing and Various Shading Effects
source	IEEE Computer Graphics & Applications 9 no. 2: 21-29
summary	A method is proposed for compositing 3-D images produced by different programs, taking depth order into consideration. The method can add the following effects to composited images: antialiased images with scaling are displayed by a simple algorithm; the algorithm can add shading effects due to various types of light, such as area sources and skylight; and ray tracing can be performed in localized regions, producing realistic results without the computational expense of ray tracing the whole image. In addition to the above processes, such shading effects as fog and texture mapping can be processed with conventional methods. Thus, it becomes possible to display complex scenes with various shading effects, using relatively small computers. The multiscanning method used for antialiasing and a data structure for processing it are described. Examples are presented to demonstrate the capability of the system.
series	journal paper
last changed	2003/04/23 15:14

_id	sigradi2006_e028c
id	sigradi2006_e028c
authors	Griffith, Kenfield; Sass, Larry and Michaud, Dennis
year	2006
title	A strategy for complex-curved building design:Design structure with Bi-lateral contouring as integrally connected ribs
source	SIGraDi 2006 - [Proceedings of the 10th Iberoamerican Congress of Digital Graphics] Santiago de Chile - Chile 21-23 November 2006, pp. 465-469
summary	Shapes in designs created by architects such as Gehry Partners (Shelden, 2002), Foster and Partners, and Kohn Peterson and Fox rely on computational processes for rationalizing complex geometry for building construction. Rationalization is the reduction of a complete geometric shape into discrete components. Unfortunately, for many architects the rationalization is limited reducing solid models to surfaces or data on spread sheets for contractors to follow. Rationalized models produced by the firms listed above do not offer strategies for construction or digital fabrication. For the physical production of CAD description an alternative to the rationalized description is needed. This paper examines the coupling of digital rationalization and digital fabrication with physical mockups (Rich, 1989). Our aim is to explore complex relationships found in early and mid stage design phases when digital fabrication is used to produce design outcomes. Results of our investigation will aid architects and engineers in addressing the complications found in the translation of design models embedded with precision to constructible geometries. We present an algorithmically based approach to design rationalization that supports physical production as well as surface production of desktop models. Our approach is an alternative to conventional rapid prototyping that builds objects by assembly of laterally sliced contours from a solid model. We explored an improved product description for rapid manufacture as bilateral contouring for structure and panelling for strength (Kolarevic, 2003). Infrastructure typically found within aerospace, automotive, and shipbuilding industries, bilateral contouring is an organized matrix of horizontal and vertical interlocking ribs evenly distributed along a surface. These structures are monocoque and semi-monocoque assemblies composed of structural ribs and skinning attached by rivets and adhesives. Alternative, bi-lateral contouring discussed is an interlocking matrix of plywood strips having integral joinery for assembly. Unlike traditional methods of building representations through malleable materials for creating tangible objects (Friedman, 2002), this approach constructs with the implication for building life-size solutions. Three algorithms are presented as examples of rationalized design production with physical results. The first algorithm [Figure 1] deconstructs an initial 2D curved form into ribbed slices to be assembled through integral connections constructed as part of the rib solution. The second algorithm [Figure 2] deconstructs curved forms of greater complexity. The algorithm walks along the surface extracting surface information along horizontal and vertical axes saving surface information resulting in a ribbed structure of slight double curvature. The final algorithm [Figure 3] is expressed as plug-in software for Rhino that deconstructs a design to components for assembly as rib structures. The plug-in also translates geometries to a flatten position for 2D fabrication. The software demonstrates the full scope of the research exploration. Studies published by Dodgson argued that innovation technology (IvT) (Dodgson, Gann, Salter, 2004) helped in solving projects like the Guggenheim in Bilbao, the leaning Tower of Pisa in Italy, and the Millennium Bridge in London. Similarly, the method discussed in this paper will aid in solving physical production problems with complex building forms. References Bentley, P.J. (Ed.). Evolutionary Design by Computers. Morgan Kaufman Publishers Inc. San Francisco, CA, 1-73 Celani, G, (2004) “From simple to complex: using AutoCAD to build generative design systems” in: L. Caldas and J. Duarte (org.) Implementations issues in generative design systems. First Intl. Conference on Design Computing and Cognition, July 2004 Dodgson M, Gann D.M., Salter A, (2004), “Impact of Innovation Technology on Engineering Problem Solving: Lessons from High Profile Public Projects,” Industrial Dynamics, Innovation and Development, 2004 Dristas, (2004) “Design Operators.” Thesis. Massachusetts Institute of Technology, Cambridge, MA, 2004 Friedman, M, (2002), Gehry Talks: Architecture + Practice, Universe Publishing, New York, NY, 2002 Kolarevic, B, (2003), Architecture in the Digital Age: Design and Manufacturing, Spon Press, London, UK, 2003 Opas J, Bochnick H, Tuomi J, (1994), “Manufacturability Analysis as a Part of CAD/CAM Integration”, Intelligent Systems in Design and Manufacturing, 261-292 Rudolph S, Alber R, (2002), “An Evolutionary Approach to the Inverse Problem in Rule-Based Design Representations”, Artificial Intelligence in Design ’02, 329-350 Rich M, (1989), Digital Mockup, American Institute of Aeronautics and Astronautics, Reston, VA, 1989 Schön, D., The Reflective Practitioner: How Professional Think in Action. Basic Books. 1983 Shelden, D, (2003), “Digital Surface Representation and the Constructability of Gehry’s Architecture.” Diss. Massachusetts Institute of Technology, Cambridge, MA, 2003 Smithers T, Conkie A, Doheny J, Logan B, Millington K, (1989), “Design as Intelligent Behaviour: An AI in Design Thesis Programme”, Artificial Intelligence in Design, 293-334 Smithers T, (2002), “Synthesis in Designing”, Artificial Intelligence in Design ’02, 3-24 Stiny, G, (1977), “Ice-ray: a note on the generation of Chinese lattice designs” Environmental and Planning B, volume 4, pp. 89-98
keywords	Digital fabrication; bilateral contouring; integral connection; complex-curve
series	SIGRADI
email
last changed	2016/03/10 09:52

_id	1920
authors	Riesbeck, C. and Schank, R.C.
year	1989
title	Inside Case-based Reasoning
source	Lawrence Erlbaum Associates, Hillsdale, NJ
summary	Case-based reasoning, broadly construed, is the process of solving new problems based on the solutions of similar past problems. An auto mechanic who fixes an engine by recalling another car that exhibited similar symptoms is using case-based reasoning. A lawyer who advocates a particular outcome in a trial based on legal precedents is using case-based reasoning. It has been argued that case-based reasoning is not only a powerful method for computer reasoning, but also a pervasive behavior in everyday human problem solving. Case-based reasoning (CBR) has been formalized as a four-step process:N 1. Retrieve: Given a target problem, retrieve cases from memory that are relevant to solving it. A case consists of a problem, its solution, and, typically, annotations about how the solution was derived. For example, suppose Fred wants to prepare blueberry pancakes. Being a novice cook, the most relevant experience he can recall is one in which he successfully made plain pancakes. The procedure he followed for making the plain pancakes, together with justifications for decisions made along the way, constitutes Fred's retrieved case. 2. Reuse: Map the solution from the previous case to the target problem. This may involve adapting the solution as needed to fit the new situation. In the pancake example, Fred must adapt his retrieved solution to include the addition of blueberries. 3. Revise: Having mapped the previous solution to the target situation, test the new solution in the real world (or a simulation) and, if necessary, revise. Suppose Fred adapted his pancake solution by adding blueberries to the batter. After mixing, he discovers that the batter has turned blue -- an undesired effect. This suggests the following revision: delay the addition of blueberries until after the batter has been ladled into the pan. 4. Retain: After the solution has been successfully adapted to the target problem, store the resulting experience as a new case in memory. Fred, accordingly, records his newfound procedure for making blueberry pancakes, thereby enriching his set of stored experiences, and better preparing him for future pancake-making demands. At first glance, CBR may seem similar to the rule-induction algorithmsP of machine learning.N Like a rule-induction algorithm, CBR starts with a set of cases or training examples; it forms generalizations of these examples, albeit implicit ones, by identifying commonalities between a retrieved case and the target problem. For instance, when Fred mapped his procedure for plain pancakes to blueberry pancakes, he decided to use the same basic batter and frying method, thus implicitly generalizing the set of situations under which the batter and frying method can be used. The key difference, however, between the implicit generalization in CBR and the generalization in rule induction lies in when the generalization is made. A rule-induction algorithm draws its generalizations from a set of training examples before the target problem is even known; that is, it performs eager generalization. For instance, if a rule-induction algorithm were given recipes for plain pancakes, Dutch apple pancakes, and banana pancakes as its training examples, it would have to derive, at training time, a set of general rules for making all types of pancakes. It would not be until testing time that it would be given, say, the task of cooking blueberry pancakes. The difficulty for the rule-induction algorithm is in anticipating the different directions in which it should attempt to generalize its training examples. This is in contrast to CBR, which delays (implicit) generalization of its cases until testing time -- a strategy of lazy generalization. In the pancake example, CBR has already been given the target problem of cooking blueberry pancakes; thus it can generalize its cases exactly as needed to cover this situation. CBR therefore tends to be a good approach for rich, complex domains in which there are myriad ways to generalize a case.
series	other
last changed	2003/04/23 15:14

_id	4cf3
authors	Kalay, Yehuda E.
year	1989
title	Modeling Objects and Environments
source	xix, 402 p. : ill. New York: Wiley, 1989. includes a short bibliography and index. Part of the Principles of Computer Aided Design series. --- See also review by Patricia G
summary	McIntosh, in ACADIA Newsletter Vol. 9 No. 3 pp 20-23, June 1990. This book introduces the concept of modeling objects in the computer's memory so it can be used to aide the process of their design. Modeling is defined as an hierarchical abstraction of data and operators to manipulate it, subject to semantic integrity constraints that guarantee the realizability of the designed artifact in the real world. Starting with general concepts of modeling, the book moves on to discuss the modeling of shapes (form) in two and in three dimensions. The discussion covers both topology and geometry. Next the book introduces the concept of shape transformations (translation, scaling, rotation, etc.), both in absolute and in relative terms. The book then introduces the concept of assembly modeling, and adds non-graphical attributes to the representation. It concludes with a discussion on user interface and parametrization. The book includes many examples written in Pascal that complement the theory, and can be used as a basis for building a geometric modeling engine. It also includes exercises, so it can be used as a text book for a two-semester advance course in geometric modeling
keywords	CAD, data structures, solid modeling, abstraction, polygons, solids, boolean operations, transforms, computer graphics, user interface, parametrization, B-rep, polyhedra, objects, PASCAL
series	CADline
email
last changed	2003/06/02 13:58

_id	a68b
authors	Mackenzie, C.A.
year	1989
title	Inferring Relational Design Grammars
source	Environment and Planning B. 1989. vol. 16: pp. 252-287
summary	The hierarchical structure afforded by linguistic systems, together with inter-element relationships, is suggested as a means of representing interpretations of generative design processes. The utility of relational descriptions for describing spatial arrangements and performing geometric transformations is discussed. Tree systems are shown to be a useful representation for relational descriptions, by making explicit the possible hierarchical organizations, and a search mechanism is introduced to look for 'interesting' design interpretations. A method for inferring tree automata from positive sample sets is employed to infer relational grammars. Issues in the representation and the grammatical inference method are discussed in the light of examples from the domain of spatial configuration
keywords	inference, shape grammars, design, synthesis, relations, search
series	CADline
last changed	2003/06/02 13:58

_id	2ea6
authors	Novak, Marcos
year	1989
title	An Experiment in Computational Composition
source	New Ideas and Directions for the 1990’s [ACADIA Conference Proceedings] Gainsville (Florida - USA) 27-29 October 1989, pp. 61-83
doi	https://doi.org/10.52842/conf.acadia.1989.061
summary	A compositional study based on a visual interpretation of information theory is introduced. An algorithm is presented that relates variety in spatial parameters to visual information, along with a genetically inspired mechanism for refining a design through cycles of incremental cumulative changes. Two- and three-dimensional examples are shown.
series	ACADIA
email
last changed	2022/06/07 08:00

_id	ea2d
authors	Schmitt, Gerhard
year	1990
title	Classes of Design-Classes of Tools
source	The Electronic Design Studio: Architectural Knowledge and Media in the Computer Era [CAAD Futures ‘89 Conference Proceedings / ISBN 0-262-13254-0] Cambridge (Massachusetts / USA), 1989, pp. 77-90
summary	It is unrealistic to expect one computer-aided design tool to sufficiently support any one given design process. Yet it is necessary to define new CAD programs that give semantic support in design. To this end, the paper first differentiates phases and classes of design and then attempts to establish relations between the defined classes and appropriate computer-aided design tools. In three main sections it describes (i) routine, innovative and creative design, (ii) a set of corresponding prototype design tools, and (iii) two examples of routine and innovative design which use these tools. The purpose of the paper is to make a contribution to the definition of domain specific aspects of CAD and to propose a mapping between processes and tools.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	0e93
authors	Af Klercker, Jonas
year	1989
title	Interactive Animation on the Macintosh II
source	CAAD: Education - Research and Practice [eCAADe Conference Proceedings / ISBN 87-982875-2-4] Aarhus (Denmark) 21-23 September 1989, pp. 9.5.1-9.5.6
doi	https://doi.org/10.52842/conf.ecaade.1989.x.a0t
summary	The efficiency of images in communication between humans has so far been used almost exclusively by TV and other mass medias. The costs have been too great to encourage the use of images in the financially restricted everyday practice of architecture. With a range of application programs for the Apple Macintosh II the vision has come close to reality. It is now possible to create guided walks with the chance to choose different routes and views in a model of buildings and surroundings in 256 colour graphics. The makers of these programs may not have foreseen this use for their products and that is why it takes quite a lot of effort to make all the necessary images. With some supplementary routines however, this will be made much easier. Animation can also be used to visualize different processes inside a building. We have been studying the working environment in mechanical industry. The goal of this project is to make communication possible between the workers at all levels of an organization in planning changes and has so far been very successful. The use of this technique is only limited by our imagination and funding. Some examples to be tested in the near future are "Escape at a fire", "Animation of a Dairy", "Traffic situations in a parking lot-, "CAD-working place" and others. One of the difficulties in interactive planning with users has been to come close enough to their reality. With animated images it is possible to visualize what is going to happen and what it is going to look like in a more understandable way. In education this must be a challenging possibility. Changes and processes are some of the most difficult subjects to describe and explain! The software used is a handful of individual programs which, thanks to the graphics standards of the Macintosh, can exchange data with each other.
series	eCAADe
email
more	http://www.caad.lth.se/
last changed	2022/06/07 07:50

_id	4032
authors	Barron, Christopher L.
year	1989
title	3-D Modelling
source	architectural and Engineering Systems. April, 1989. [41] -56 unevenly numbered
summary	From screen to structure, more and more AEs are finding design solutions in the third dimension. The author reviews current 3-D modeling systems, what are the expectations of the users and the developers goals
keywords	architecture, practice, drafting, modeling, systems
series	CADline
last changed	2003/06/02 13:58

_id	82b9
authors	Beyers, Robert and Desa, Subhas
year	1989
title	Design of Control Systems for Performance : A Constraint Mapping Approach
source	17 p. : ill Engineering Design Research Center, CMU, October, 1989. EDRC 24-10-89. includes bibliography.
summary	Simple s-plane maps are used to graphically reveal interactions of performance requirements and constraints thus providing a control system designer insight into performance trade-offs. Two well-known but powerful ideas underlie this approach: (a) the characteristic equation of an nth-order system can be fully described by the specification of n variables and (b) any dynamic performance requirement or constraint can be expressed in terms of 2n variables of which n describe the open-loop and n describe the closed-loop characteristic equations. An example illustrates the application of the approach to controller design
keywords	constraints, engineering, control, systems, design, performance
series	CADline
last changed	2003/06/02 13:58

_id	6a30
authors	Bonn, Markus
year	1989
title	Modeling Architectural Forms through Replacement Operations
source	New Ideas and Directions for the 1990’s [ACADIA Conference Proceedings] Gainsville (Florida - USA) 27-29 October 1989, pp. 103-130
doi	https://doi.org/10.52842/conf.acadia.1989.103
summary	Replacement operations, where an element at any topological level may be replaced by another element at the same or different topological level, are defined. Their potential as design tools which may be incorporated in a CAD system is investigated and demonstrated through the experimental implementation of two such operations in MARCOS, a Modeling Architectural Compositions System. MARCOS has been written in C. It is highly interactive and runs on an Apple Macintosh IIx. The two operations which have been implemented are the face -> volume and volume -> volume replacements. They were chosen for their potential as generators of architectural forms. Examples of architectural compositions produced through the use of replacement operations are also illustrated.
series	ACADIA
email
last changed	2022/06/07 07:54

_id	b4c4
authors	Carrara, G., Fioravanti, A. and Novembri, G.
year	2000
title	A framework for an Architectural Collaborative Design
source	Promise and Reality: State of the Art versus State of Practice in Computing for the Design and Planning Process [18th eCAADe Conference Proceedings / ISBN 0-9523687-6-5] Weimar (Germany) 22-24 June 2000, pp. 57-60
doi	https://doi.org/10.52842/conf.ecaade.2000.057
summary	The building industry involves a larger number of disciplines, operators and professionals than other industrial processes. Its peculiarity is that the products (building objects) have a number of parts (building elements) that does not differ much from the number of classes into which building objects can be conceptually subdivided. Another important characteristic is that the building industry produces unique products (de Vries and van Zutphen, 1992). This is not an isolated situation but indeed one that is spreading also in other industrial fields. For example, production niches have proved successful in the automotive and computer industries (Carrara, Fioravanti, & Novembri, 1989). Building design is a complex multi-disciplinary process, which demands a high degree of co-ordination and co-operation among separate teams, each having its own specific knowledge and its own set of specific design tools. Establishing an environment for design tool integration is a prerequisite for network-based distributed work. It was attempted to solve the problem of efficient, user-friendly, and fast information exchange among operators by treating it simply as an exchange of data. But the failure of IGES, CGM, PHIGS confirms that data have different meanings and importance in different contexts. The STandard for Exchange of Product data, ISO 10303 Part 106 BCCM, relating to AEC field (Wix, 1997), seems to be too complex to be applied to professional studios. Moreover its structure is too deep and the conceptual classifications based on it do not allow multi-inheritance (Ekholm, 1996). From now on we shall adopt the BCCM semantic that defines the actor as "a functional participant in building construction"; and we shall define designer as "every member of the class formed by designers" (architects, engineers, town-planners, construction managers, etc.).
keywords	Architectural Design Process, Collaborative Design, Knowledge Engineering, Dynamic Object Oriented Programming
series	eCAADe
email
more	http://www.uni-weimar.de/ecaade/
last changed	2022/06/07 07:55

_id	235d
authors	Catalano, Fernando
year	1990
title	The Computerized Design Firm
source	The Electronic Design Studio: Architectural Knowledge and Media in the Computer Era [CAAD Futures ‘89 Conference Proceedings / ISBN 0-262-13254-0] Cambridge (Massachusetts / USA), 1989, pp. 317-332
summary	This paper is not just about the future of computerized design practice. It is about what to do today in contemplation of tomorrow-the issues of computercentered practice and the courses of action open to us can be discerned by the careful observer. The realities of computerized design practice are different from the issues on which design education still fixes its attention. To educators, the present paper recommends further clinical research on computerized design firms and suggests that case studies on the matter be developed and utilized as teaching material. Research conducted by the author of this paper indicates that a new form of design firm is emerging-the computerized design firm-totally supported and augmented by the new information technology. The present paper proceeds by introducing an abridged case study of an actual totally electronic, computerized design practice. Then, the paper concentrates on modelling the computerized design firm as an intelligent system, indicating non-trivial changes in its structure and strategy brought about by the introduction of the new information technology into its operations - among other considerations, different strategies and diverse conceptions of management and workgroup roles are highlighted. In particular, this paper points out that these structural and strategic changes reflect back on the technology of information with pressures to redirect present emphasis on the individual designer, working alone in an isolated workstation, to a more realistic conception of the designer as a member of an electronic workgroup. Finally, the paper underlines that this non-trivial conception demands that new hardware and software be developed to meet the needs of the electronic workgroup - which raises issues of human-machine interface. Further, it raises the key issues of how to represent and expose knowledge to users in intelligent information - sharing systems, designed to include not only good user interfaces for supporting problem-solving activities of individuals, but also good organizational interfaces for supporting the problem-solving activities of groups. The paper closes by charting promising directions for further research and with a few remarks about the computerized design firm's (near) future.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	801b
authors	Cocchioni, Cristina and Mecca, Saverio
year	1989
title	Utilization of Rules for Modular Coordination in Relational Models to Be Employed In CAAD
source	CAAD: Education - Research and Practice [eCAADe Conference Proceedings / ISBN 87-982875-2-4] Aarhus (Denmark) 21-23 September 1989, pp. 7.5.1-7.5.11
doi	https://doi.org/10.52842/conf.ecaade.1989.x.p3f
summary	The paper deals with the structure of experimental software to be used for the interactive relational database and a graphic package. Proposed is the development that considers the main implications of a modular space grid for the project´s development already from the stage of preliminary wire-frame design.
series	eCAADe
last changed	2022/06/07 07:50

_id	ee16
authors	Coyne, R.D., Newton, S. and Sudweeks, F.
year	1989
title	Modeling the Emergence of Schemas in Design Reasoning
source	Design Computing Unit, Department of Architectural and Design Science, University of Sydney, 1989. pp. 173-205. CADLINE has abstract only
summary	The authors explore how neural networks can be used to model important aspects of design reasoning: the way design involves memory; and a 'holistic' kind of reasoning by which designs appear to emerge from that memory. A simple neural network is constructed to demonstrate how information about schemas (in this case, room types) is stored implicitly after exposure to a number of examples of specific rooms. We then demonstrate how new room types emerge from this information. The paper includes a discussion of design, a discussion of schemas from a psycholinguistic perspective, a technical explanation of neural networks and the demonstration of an implemented examples
keywords	neural networks, modeling, design, reasoning, learning, knowledge acquisition, experimentation
series	CADline
email
last changed	2003/05/17 10:13

_id	e303
authors	Coyne, Richard D. and Newton, S.
year	1989
title	A Tutorial on Neural Networks and Expert Systems for Design
source	University of Sydney, 1989. pp. 321-337. CADLINE has abstract only
summary	This paper presents an overview of neural network (connectionist) systems and their potential contribution to computer-aided design. The authors discuss the appeal of neural networks and some of the problems. The major contribution to design is in the representation and manipulation of schemas. A neural network system can be 'taught' various examples (such as room descriptions). The system then apparently recognizes schemas (room types) and can produce novel but sensible combinations of descriptions constituting new types. A simple handworked example is presented, and the learning and reasoning mechanism is explained
keywords	representation, CAD, expert systems, design, neural networks
series	CADline
email
last changed	2003/05/17 10:13

_id	c3ec
authors	Coyne, Richard D. and Radford, Antony D.
year	1989
title	Knowledge-based Design Systems in Architecture : a Linguistic Perspective
source	Knowledge Based Systems in Architecture. Helsinki: Acta Polytechnica Scandinavica, 1989. pp. 27-36
summary	The separation of syntax and semantics in systems for the production of architectural designs is discussed. In producing designs we are less interested in mapping between buildings and their meaning than in mapping between an intended meaning and a design description of a kind that can be constructed, a mapping between semantic and syntactic realms. The thesis of this paper is that it is both feasible and operationally useful to separate the consideration of interpretation and syntactic generating in design. The authors first examine the possibility of operating in the syntactic realm, then the possibility of operating in the interpretative realm. Finally they examine how a design system might combine interpretative and syntactic systems
keywords	reasoning, design, CAD, architecture, knowledge base, semantics
series	CADline
email
last changed	2003/05/17 10:13

_id	8bdf
authors	Crocker, Gary A. and Reinke, William F.
year	1989
title	Boundary Evaluation in a Non-Manifold Environment
source	November, 1989. 30 p., [16] p. of ill. includes bibliography
summary	The recent availability of Non-Manifold Topology (NMT) enables the coexistence of wireframe geometry, surfaces, and solids in a single representation with complete topological resolution. This in turn allows a new approach to boundary evaluation. This new approach merges a set of primitives into a single Boundary REPresentation (B-rep), and selects the desired Boolean results without destroying any B-rep entities. The results of the Boolean operations are displayed by drawing only selected entities. The B-rep resulting from the merge contains a complete description of the input primitives. While traditional algorithms allow incremental addition of primitives, this new approach also allows incremental deletion of primitives from the merged B-rep. Changes in Boolean operators and/or their order of evaluation can be reflected in the B-rep simply by changing the criteria of the selection process. Constructive Solid Geometry (CSG) editing operations can be mirrored in the B-rep incrementally, i.e. without performing complete reevaluation of the B-rep from its constituent primitive definitions. In addition, the domain of boundary evaluation has been extended to include Boolean operations between wireframe geometry, surfaces, and solids. This new approach has been successfully implemented and tested to boundary evaluation. Test results have shown an order of magnitude reduction in the cost associated with reflecting CSG editing operations on existing B-reps, with only minimal additional cost for initial construction. Also shown are examples of Boolean operations between solids, surfaces, and wires
keywords	computational geometry, boolean operations, solid modeling, B-rep, CSG, representation, topology, curved surfaces, intersection, curves,
series	CADline
last changed	2003/06/02 13:58

_id	298e
authors	Dave, Bharat and Woodbury, Robert
year	1990
title	Computer Modeling: A First Course in Design Computing
source	The Electronic Design Studio: Architectural Knowledge and Media in the Computer Era [CAAD Futures ‘89 Conference Proceedings / ISBN 0-262-13254-0] Cambridge (Massachusetts / USA), 1989, pp. 61-76
summary	Computation in design has long been a focus in our department. In recent years our faculty has paid particular attention to the use of computation in professional architectural education. The result is a shared vision of computers in the curriculum [Woodbury 1985] and a set of courses, some with considerable historyland others just now being initiated. We (Dave and Woodbury) have jointly developed and at various times over the last seven years have taught Computer Modeling, the most introductory of these courses. This is a required course for all the incoming freshmen students in the department. In this paper we describe Computer Modeling: its context, the issues and topics it addresses, the tasks it requires of students, and the questions and opportunities that it raises. Computer Modeling is a course about concepts, about ways of explicitly understanding design and its relation to computation. Procedural skills and algorithmic problem solving techniques are given only secondary emphasis. In essential terms, the course is about models, of design processes, of designed objects, of computation and of computational design. Its lessons are intended to communicate a structure of such models to students and through this structure to demonstrate a relationship between computation and design. It is hoped that this structure can be used as a framework, around which students can continue to develop an understanding of computers in design.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	10a5
authors	Edwards, D.M. and Hardman, L.
year	1989
title	Lost In Hyperspace: Cognitive Mapping and Navigation in a Hypertext Environment, Chapter 7
source	Hypertext: Theory Into Practice, Edited by McAleese, Ray., Ablex Publishing Corporation, New Jersey
summary	This paper describes an experiment which looks at how the users of a hypertext document cognitively represent its layout. A document was formed into three different hypertext styles and was presented to the readers, they were then asked a series of questions about information contained in the hypertexts. The way the users found the answers and the time taken was recorded, they were also ask to lay out cards, with reduced versions of the screen on them, on a board and as they thought them to be arranged in the document and also to draw any connecting hypertext links they thought existed between these screens. The users selected for this experiment consisted of 27 university undergraduates 15 male and 12 female with a mean age of 20.5 years with little or no computing experience. They were each assigned one of the three hypertext methods and their performance was recorded. The three methods consisted of a hierarchical, a mixed and an index based method.
series	other
last changed	2003/04/23 15:14

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