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	5fe7
authors	Hoffmann C.M.
year	1989
title	Geometric and Solid Modeling
source	Morgan Kaufmann
summary	Solid modeling is rapidly emerging as a central area of research and de- velopment in such diverse applications as engineering and product design, computer-aided manufacturing, electronic prototyping, o -line robot pro- gramming, and motion planning. All these applications require represent- ing the shapes of solid physical objects, and such representations and basic operations on them can be provided by solid modeling. As a eld, solid modeling spans several disciplines, including mathemat- ics, computer science, and engineering. In consequence, it is a broad subject that must accommodate a diversity of viewpoints and has to meet a diversity of goals. Sometimes, this diversity of goals can lead to con icting demands. Current thinking on the subject views the proper resolution of these con- icts to be application-dependent. That is, it is no longer thought realistic to envision a comprehensive solid-modeling system that satis es the needs of all potential users. Rather, as it is argued, we should concentrate on con- structing a software environment in which many tools for geometric and solid computation are available and can be combined with ease as appropriate for the speci c application under consideration.
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	a495
authors	Kalay, Yehuda E.
year	1989
title	The Hybrid Edge : A Topological Data Structure for Vertically Integrated Geometric Modeling
source	Computer Aided Design. April, 1989. vol. 21: pp. 129-139 : ill. includes bibliography
summary	Generalizing the computational geometric support for the representation of designed artifacts over multiple different levels of symbolic abstraction (e.g., sketches, solid modeling, and drafting) is discussed. First, the need for integrating the representation and manipulation of points, lines, polygons and solids for the purpose of facilitating the design of artifacts at many levels of design abstractions established. Second, a vertically integrated model that supports the representation and manipulation of points, lines, polygons, and solids without redundancy, is presented. The particular roles of the operators and the operandi are discussed, along with their hierarchical integration. The utility of the model is demonstrated in performing operations that involve multiple different levels of data abstraction, such as splitting solids at an arbitrary polygon inscribed on their boundary. Finally, a particular implementation of the integrated model is presented. This implementation is based on the Hybrid Edge, a derivative from Baumgart's Winged Edge and Eastman's Split Edge models. The Hybrid Edge distinguishes between the roles of edges as topological adjacency information carriers and their role as carriers of directionality information. This distinction permits the Hybrid Edge to handle the different combinations of adjacency and directionality requirements imposed by different abstraction levels in the integrated model
keywords	geometric modeling, hybrid edge, topology, solid modeling, B-rep
series	CADline
email
last changed	2003/05/17 10:18

_id	f4fb
authors	Karasick, Michael
year	1989
title	On the Representation and Manipulation of Rigid Solids
source	McGill University, Department of Computer Science, Montreal
summary	Solid modeling studies how to represent geometric properties of solids by computer. A fundamental operation is the construction of representations of solids. Algorithms for set operations construct boundary representations of solids from boundary representations of other solids. A correct and efficient intersection algorithm for polyhedral solids that uses boundary representations is described. A finite-precision implementation of the algorithm uses incidence tests that use symbolic inference in order to limit errors due to finite-precision approximations. The incidence tests are described and experimental evidence is presented to show that the incidence tests are both empirically reliable and practical. The intersection algorithm uses a new boundary representation called the Star-Edge representation. A complementation algorithm for solids that uses the new representation is given, and an algorithm is given that uses the new representation to determine if two boundary representations describe the same solid. A canonical boundary representation for solids is described and used to prove a lower bound for the same-object problem.
series	thesis:PhD
email
last changed	2003/02/12 22:37

_id	a87a
authors	Kroszynski, U.I., Palstorem, Bj. and Trostmann, E. (et al)
year	1989
title	Geometric Data Transfer Between CAD Systems : Solid Models
source	IEEE Computer Graphics and Applications September, 1989. vol. 9: pp. 57-71 : ill. includes bibliography.
summary	The CAD/CAM community is showing great interest in the development of data exchange standards. This article highlights some aspects of the work accomplished during the first phase of the ESPRIT project CAD1. Part of this work has resulted in a specification for the exchange of solid models, as well as in some pilot implementations of processors based on this specification. This work also contributes to the efforts of the International Standards Organization (ISO) in developing the Standard for the Exchange of Product Model Data (STEP). The authors present a summary of the CAD1 approach, addressing the structure of neutral files for solids, entities, and attributes supporting three kinds of representations; facilities for the transfer of parametric designs; referencing library components; and other general mechanisms. Also is described the current state of the specification and processor implementations. An example of a CAD1 neutral file is included. Results from cycle and intersystem solid model transfer tests are presented, showing the practicality of the CAD1 proposal. B-rep model transfer results are discussed in some detail. Finally, the authors outline the relationship of this work with standardization
keywords	communication, solid modeling, standards, STEP, B-rep
series	CADline
last changed	2003/06/02 14:42

_id	7812
authors	Straber, W. and Seidel, H.-P. (eds.)
year	1989
title	Theory and Practice of Geometric Modeling
source	Springer-Verlag
summary	This book originates from the lectures given at the international conference "Theory and Practice of Geometric Modeling", Blaubeuren, FRG, October 3-7, 1988, that brought together leading experts from universities, system developers, and system users, to discuss new concepts and future trends in geometric modeling. The book covers a variety of topics on an advanced level and is organized as follows. Part A contains new algorithms and techniques for modeling objects that are bounded by free form surfaces. Part B focuses on surface/surface intersections, new types of blending surfaces and speed ups for ray tracing. Part C contains some new geometric tools. Part D discusses different representation schemes in solid modeling, conversions between these different schemes, and some applications. Part E covers some issues of product modeling, automatic tolerancing, high level specification of solid models (constraints, features) and the need for better user interfaces.
series	other
last changed	2003/04/23 15:14

_id	2786
authors	Woodwark, J.R.
year	1989
title	Splitting Set-Theoretic Solid Models into Connected Components
source	10 p. : ill. Winchester: IBM UK Scientific Center, IBM United Kingdom Laboratories Limited, June, 1989. IBM UKSC 210. includes bibliography In general, there is no way to tell how many pieces (connected components) a set-theoretic (CSG) solid model represents, except via conversion to a boundary model. Recent work on the elimination of redundant primitives has been linked with techniques for identifying connected components in quad-trees and oct-trees into a strategy to attack this problem. Some success has been achieved, and an experimental Prolog program, working in two dimensions, that finds connected components and determines the set-theoretic representation of each component, is reported, and further developments proposed. CSG / quadtree / octree / primitives / algorithms. 43. Woodwark, J. R. and Quinlan K. M. 'Reducing the Effect of Complexity on Volume Model Evaluation.' Computer Aided Design. April, 1982. pp. 89-95 : ill. includes bibliography.
summary	A major problem with volume modelling systems is that processing times may increase with model complexity in a worse than linear fashion. The authors have addressed this problem, for picture generation, by repeatedly dividing the space occupied by a model, and evaluating the sub-models created only when they meet a criterion of simplicity. Hidden surface elimination has been integrated with evaluation, in such a way that major portions of the model which are not visible are never evaluated. An example demonstrates a better than linear relationship between model complexity and computation time, and also shows the effect of picture complexity on the performance of the process
keywords	CAD, computational geometry, solid modeling, geometric modeling, algorithms, hidden surfaces, CSG
series	CADline
last changed	2003/06/02 13:58

_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	22bd
authors	Hoffmann, C.M., Hopcroft, J.E. and Karasick, M.S.
year	1989
title	Robust Set Operations on Polyhedral Solids
source	IEEE Computer Graphics and Applications. November, 1989. vol. 9: pp. 50-59 : ill. includes bibliography
summary	The paper describes an algorithm for performing regularized Boolean operations on polyhedral solids. Robustness is achieved by adding symbolic reasoning as a supplemental step to resolve possible numerical uncertainty. Additionally, numerical redundancy and numerical computation based on derived quantities are reduced as much as possible. It also discusses the authors' experience with the implementation of the algorithm
keywords	algorithms, polyhedra, solids, representation, computational geometry, geometric modeling, boolean operations
series	CADline
last changed	2003/06/02 14:41

_id	ac36
authors	McCullough, Malcolm
year	1990
title	Low-Threshold Modeling
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. 413-426
summary	This is a case study of teaching at the University of Texas at Austin. It is about using an electronic design studio to provide architecture students with their first exposure to computing. It suggests that, despite the limitations of present technology, there is reason to lower the thresholds to computer-aided design. The study presents a studio which attempted such by allowing students to find their own level of commitment to use of electronic media for geometric modeling. More generally, the paper aims to document issues presently facing the many professional schools not having substantial traditions in computer-aided design education.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	e91f
authors	Mitchell, W.J., Liggett, R.S. and Tan, M.
year	1990
title	Top-Down Knowledge-Based Design
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. 137-148
summary	Traditional computer drafting systems and three- dimensional geometric modeling systems work in bottom-up fashion. They provide a range of graphic primitives, such as vectors, arcs, and splines, together with operators for inserting, deleting, combining, and transforming instances of these. Thus they are conceptually very similar to word processors, with the difference that they operate on two- dimensional or three-dimensional patterns of graphic primitives rather than one-dimensional strings of characters. This sort of system is effective for input and editing of drawings or models that represent existing designs, but provides little more help than a pencil when you want to construct from scratch a drawing of some complex object such as a human figure, an automobile, or a classical column: you must depend on your own knowledge of what the pieces are and how to shape them and put them together. If you already know how to draw something then a computer drafting system will help you to do so efficiently, but if you do not know how to begin, or how to develop and refine the drawing, then the efficiency that you gain is of little practical consequence. And accelerated performance, flashier color graphics, or futuristic three-dimensional modes of interaction will not help with this problem at all. By contrast, experienced expert graphic artists and designers usually work in top-down fashion-beginning with a very schematic sketch of the whole object, then refining this, in step-by-step fashion, till the requisite level of precision and completeness is reached. For example, a figure drawing might begin as a "stick figure" schema showing lengths and angles of limbs, then be developed to show the general blocking of masses, and finally be resolved down to the finest details of contour and surface. Similarly, an architectural drawing might begin as a parti showing just a skeleton of construction lines, then be developed into a single-line floor plan, then a plan showing accurate wall thicknesses and openings, and finally a fully developed and detailed drawing.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	effd
authors	Morozumi, M., Nakamura, H. and Kijima, Y.
year	1990
title	A Primitive-Instancing Interactive 3-D Modeling System for Spatial Design Studies
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. 457-468
summary	The authors have developed a basic, interactive, primitive-instancing 3-D modeling system (CAADF), which is based on a high-speed 3-D color graphic workstation, and have tested its potential ability to support spatial design studies in an architectural design studio. After- a review of work performed by a student with the system, this paper concludes that this system provides an attractive environment for spatial design studies which conventional CAD systems have not achieved. The interactive process of 3-D modeling in perspective or isometric view images and the dynamic viewing utility are the most successful features of the system. In contrast to those advantages, the resolution of color graphic display is a limitation of the system. The authors conclude that if sufficiently many appropriate 3-D geometric primitives are supported by a CAD system, a primitive instancing method can significantly reduce the work entailed in object modeling.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	0565
authors	Oxman, Robert and Oxman, Rivka
year	1990
title	The Computability of Architectural Knowledge
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. 171-185
summary	In an important contribution to the theoretical foundation of design computing, Mitchell noted "an increasingly urgent need to establish a demonstrably sound, comprehensive, rigorously formalized theoretical foundation upon which to base practical software development efforts" (Mitchell, 1986). In this paper we propose such a theoretical framework. A basic assumption of this work is that the advancement of design computing is dependent upon the emergence of a rigorous formulation of knowledge in design. We present a model of knowledge in architectural design which suggests a promising conceptual basis for dealing with knowledge in computer-aided design systems. We require models which can represent the formal knowledge and manipulative operations of the designer in all of their complexity-that is formal models rather than just geometric models. Shape Grammars (Stiny,1980) represent an example of such models, and constitute a relatively high level of design knowledge as compared to, for example, use of symmetry operations to generate simple formal configurations. Building upon an understanding of the classes of design knowledge as the conceptual basis for formal modeling systems may contribute a new realization of the potential of the medium for design. This will require a comprehensive approach to the definition of architectural and design knowledge. We consider here the implications of a well-defined body of architectural and design knowledge for design education and the potential mutual interaction-in a knowledge-rich environment-of design learning and CAAD learning. The computational factors connected with the representation of design knowledge and its integration in design systems are among the key problems of CAAD. Mitchell's model of knowledge in design incorporates formal knowledge in a comprehensive, multi-level, hierarchical structure in which types of knowledge are correlated with computational concepts. In the main focus of this paper we present a structured, multi-level model of design knowledge which we discuss with respect to current architectural theoretical considerations. Finally, we analyze the computational and educational relevance of such models.
series	CAAD Futures
email
last changed	2003/05/16 20:58

_id	ce38
authors	Paoluzzi, Alberto and Sansoni, Claudio
year	1989
title	A Programming Language for Architectural Symbolic Modeling
source	CAAD: Education - Research and Practice [eCAADe Conference Proceedings / ISBN 87-982875-2-4] Aarhus (Denmark) 21-23 September 1989, pp. 8.4.1-8.4.16
doi	https://doi.org/10.52842/conf.ecaade.1989.x.r3e
summary	In this paper a software project supporting architectural design is outlined. Such a project aims to develop the new design language PLASM (a Programming Language for Architectural Symbolic Modeling), which is planned to be a very high-level, user-oriented language, belonging to the class of constraint languages. The language PLASM will support a small set of abstract data types which are significant in various outstanding problems of architectural design, and will offer both procedural features and non-procedural constraints satisfaction. It will allow the designer to make use of a large set of computing tools in any phase of architectural design, in order to explore a wider set of design solutions. Customizable evaluation functions will be available in the language. The execution of a PLASM program may result either in generating or in updating a semantic network over a set of data objects solving the geometric problem under consideration. The proposed language will support both abstract data types significant in the design domain, and tools performing automatized data generation and transformations between different data types. The modification of any object in such a system, both performed by editing a daemon program and/or by interactively modifying a data object, will result in the immediate propagation of changes into the problem network, by activating a message passing mechanism.
series	eCAADe
email
last changed	2022/06/07 07:50

_id	cf15
authors	Penttilä, Hannu
year	1989
title	Computer Aided Building Modeling
source	CAAD: Education - Research and Practice [eCAADe Conference Proceedings / ISBN 87-982875-2-4] Aarhus (Denmark) 21-23 September 1989, pp. 3.2.1-3.2.11
doi	https://doi.org/10.52842/conf.ecaade.1989.x.d2h
summary	The subject of computer-aided building modeling is often discussed in various contexts, sometimes without clear explanation of what is modelled. Usually modeling refers to 3-dimensional geometric modeling, but nowadays also conceptual modeling and mathematical simulation aspects are more and more evident. Building modeling should though be considered more widely than just plain geometric visualization. This paper establishes one common framework for discussion about different building modeling viewpoints arranging discipline viewpoints, approach methods, existing standards and application tools within one context. Although several viewpoints are declared conceptual building modeling is regarded the main emphasis of this paper, since it definitely will be one of the key issues in developing methods and tools for computer integrated construction (CIC) in the future.
keywords	Building Modeling, Building Information and Data, Product Modeling, Conceptual Modeling, Geometric Modeling, Standards, Application Programs
series	eCAADe
email
more	http://www.tut.fi/~penttila/index.html
last changed	2022/06/07 07:50

_id	3964
authors	Yoshikawa, H. and Gossard, D. (eds.)
year	1989
title	Intelligent CAD
source	North-Holland, Amsterdam, pp. vii-ix
summary	In this research, design process knowledge is represented at two different levels, action level and object level, corresponding to the meta-knowledge to model design behaviors and the special knowledge to model the processes in designing particular objects. A design knowledge base and database modeling language - Integrated Data Description Language (IDDL) was developed at the University of Tokyo to model both design processes and design objects. This language combines logic programming functions and object oriented programming functions into an integrated environment. Using this language, an intelligent CAD system - Intelligent Integrated Interactive CAD (IIICAD) was developed at the University of Tokyo. Contradictions of knowledge base and database are resolved using circumscription and Assumption-based Truth Maintenance System (ATMS) in this system. Many advanced knowledge modeling techniques, including Qualitative Process Theory (QPT), modal logic, default reasoning, etc., have also been introduced in the IIICAD system. The knowledge base and database representation scheme of IDDL serves as the basis in the feature-based integrated concurrent design system. In the integrated concurrent design system, a new feature modeling language was introduced. In addition to the qualitative and quantitative data/relations that were introduced in IDDL, the composing element features, data dependency relations, constraints, 2D and 3D feature geometric descriptions have also been introduced for representing product life-cycle models and their relations. Optimization functions were added to the integrated concurrent design system to identify the optimal design considering relevant life-cycle aspects.
series	other
last changed	2003/04/23 15:14

_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	8ca2
authors	Miller, Frank C.
year	1990
title	Form Processing Workshop: Architectural Design and Solid Modeling at MIT
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. 441-455
summary	Computing impacts the preliminary architectural design process as a tool for observation and analysis, as a formal prototyping tool, and as a vehicle to generate variations of objects and assemblies. Through the use of both traditional and computing tools, the Form Processing Workshop examines the relationship between design decisions and design tools. The Workshop utilizes several software applications, with emphasis on the use of a solid modeler. This curriculum was developed with the support of MIT's Project Athena.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	c9f3
authors	Shaviv, Edna
year	1989
title	Implementation of Solid Modeling in High Hierarchy Architectural Language (HHAL)
source	CAAD: Education - Research and Practice [eCAADe Conference Proceedings / ISBN 87-982875-2-4] Aarhus (Denmark) 21-23 September 1989, pp. 8.2.1.8.2.21
doi	https://doi.org/10.52842/conf.ecaade.1989.x.a0j
summary	This work illustrates the use of solid modeling for the representation and analysis of complex architectural structures and details. While the approach is a general one it is demonstrated and implemented on the visual representation and evaluation of Mediaeval Age basilican structures. Basilican structures have the advantage that rules of composition for defining their form are well formulated. These rules are imposed on the solid modeler as high hierarchy architectural language (HHALL). It is within this language that the basilican structures are described and analyzed.
keywords	High Hierarchy Architectural Language (HHAL), Solid Modeling, Shape Grammar, Formal Language, Design Systems, Basilican Structures
series	eCAADe
email
last changed	2022/06/07 07:50

_id	29d2
authors	Barsky, Brian A. and DeRose,Tony D.
year	1989
title	Geometric Continuity of Parametric Curves: Three Equivalent Characterizations
source	IEEE Computer Graphics and Applications. November, 1989. vol. 9: pp. 60-68 : ill. includes bibliography
summary	Geometric continuity of curves has received a good deal of research attention in recent years. The purpose of this article is to distill some of the important basic results into a self-contained presentation. The January 1990 issue of CG&M presents a paper that continues the discussion by offering applications of the theoretical background provided here
keywords	continuity, parametrization, curves, computational geometry, representation
series	CADline
last changed	2003/06/02 13:58

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