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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	cf2003_m_040
id	cf2003_m_040
authors	BAY, Joo-Hwa
year	2003
title	Making Rebuttals Available Digitally for Minimising Biases in Mental Judgements
source	Digital Design - Research and Practice [Proceedings of the 10th International Conference on Computer Aided Architectural Design Futures / ISBN 1-4020-1210-1] Tainan (Taiwan) 13–15 October 2003, pp. 147-156
summary	The problem of heuristic biases (illusions) discussed by Tversky and Kahneman (1982) that can lead to errors in judgement by human designers, when they use precedent knowledge presented graphically (Bay 2001). A Cognitive framework of belief, goal, and decision, and a framework of representation of architectural knowledge by Tzonis are used to map out the problem of heuristic biases in the human mind. These are used to discuss what aspects of knowledge can be presented explicitly and digitally to users to make rebuttal more available for human thinking at the cognitive level. The discussion is applicable to both inductive and analytic digital knowledge systems that use precedent knowledge. This discussion is targeted directly at means of addressing bias in the human mind using digital means. The problem of human bias in machine learning and generalisation are discussed in a different paper, and the problems of international or non-intentional machine bias are not part of discussion in this paper.
keywords	analogy, bias, design thinking, environmental design, heuristics
series	CAAD Futures
last changed	2003/11/22 07:26

_id	a747
authors	Eastman, Charles M.
year	1982
title	Recent Developments in Representation in the Science of Design
source	9 p. : ill. Pittsburgh: Design Research Center, CMU, April, 1982. includes bibliography
summary	A recent goal in computer aided design is the representation of a design artifact in a form sufficient to support all analyses and to determine that the design is realizable. In this paper, the implications of the development of computer representations for design specifications are reviewed, some components of a theory of design representations are discussed, and the benefits of such a theory outlined
keywords	CAD, theory, design, representation, architecture, geometric modeling
series	CADline
email
last changed	2003/05/17 10:15

_id	e234
authors	Kalay, Yehuda E. and Harfmann, Anton C.
year	1985
title	An Integrative Approach to Computer-Aided Design Education in Architecture
source	February, 1985. [17] p. : [8] p. of ill
summary	With the advent of CAD, schools of architecture are now obliged to prepare their graduates for using the emerging new design tools and methods in architectural practices of the future. In addition to this educational obligation, schools of architecture (possibly in partnership with practicing firms) are also the most appropriate agents for pursuing research in CAD that will lead to the development of better CAD software for use by the profession as a whole. To meet these two rather different obligations, two kinds of CAD education curricula are required: one which prepares tool- users, and another that prepares tool-builders. The first educates students about the use of CAD tools for the design of buildings, whereas the second educates them about the design of CAD tools themselves. The School of Architecture and Planning in SUNY at Buffalo has recognized these two obligations, and in Fall 1982 began to meet them by planning and implementing an integrated CAD environment. This environment now consists of 3 components: a tool-building sequence of courses, an advanced research program, and a general tool-users architectural curriculum. Students in the tool-building course sequence learn the principles of CAD and may, upon graduation, become researchers and the managers of CAD systems in practicing offices. While in school they form a pool of research assistants who may be employed in the research component of the CAD environment, thereby facilitating the design and development of advanced CAD tools. The research component, through its various projects, develops and provides state of the art tools to be used by practitioners as well as by students in the school, in such courses as architectural studio, environmental controls, performance programming, and basic design courses. Students in these courses who use the tools developed by the research group constitute the tool-users component of the CAD environment. While they are being educated in the methods they will be using throughout their professional careers, they also act as a 'real-world' laboratory for testing the software and thereby provide feedback to the research component. The School of Architecture and Planning in SUNY at Buffalo has been the first school to incorporate such a comprehensive CAD environment in its curriculum, thereby successfully fulfilling its obligation to train students in the innovative methods of design that will be used in architectural practices of the future, and at the same time making a significant contribution to the profession of architecture as a whole. This paper describes the methodology and illustrates the history of the CAD environment's implementation in the School
keywords	CAD, architecture, education
series	CADline
email
last changed	2003/06/02 13:58

_id	e5d0
authors	Lowe, John P.
year	1994
title	Computer-Aided-Design in the Studio Setting: A Paradigm Shift in Architectural Education
source	The Virtual Studio [Proceedings of the 12th European Conference on Education in Computer Aided Architectural Design / ISBN 0-9523687-0-6] Glasgow (Scotland) 7-10 September 1994, p. 230
doi	https://doi.org/10.52842/conf.ecaade.1994.x.g6j
summary	The introduction of the personal computer in 1982 set forth a revolution that will continue to transform the profession of Architecture. Most architectural practices in America have embraced this revolution realizing the potentials of the computer. However, education seems to have been slower accepting the potentials and challenges of computers. Computer technology will change the design studio setting and therefore the fundamental way architects are educated. The Department of Architecture at Kansas State University has made a commitment to move toward a computer based design studio. In the fall of 1990, discussions began among the faculty to search for the placement of a computer studio within the five year program. Curriculum, staffing, and funding were issues that had to be overcome to make this commitment work. The strategy that was adopted involved placing the computer studio at the fourth year level in phase one. Phase two will progress as more staff are trained on the computer and course work was adapted to accommodate other year levels for a computer based design studios. Funding was a major obstacle. The decision was made to move from a position of being the primary suppliers of computing technology to one of support for student purchased computers. This strategy alleviated the department from maintaining and upgrading the technology. There was great enthusiasm and support from the faculty as a whole for the use of computers in the studio setting. However, the pedagogical impacts of such a change are just beginning to be realized.
series	eCAADe
last changed	2022/06/07 07:50

_id	c7e9
authors	Maver, T.W.
year	2002
title	Predicting the Past, Remembering the Future
source	SIGraDi 2002 - [Proceedings of the 6th Iberoamerican Congress of Digital Graphics] Caracas (Venezuela) 27-29 november 2002, pp. 2-3
summary	Charlas Magistrales 2There never has been such an exciting moment in time in the extraordinary 30 year history of our subject area, as NOW,when the philosophical theoretical and practical issues of virtuality are taking centre stage.The PastThere have, of course, been other defining moments during these exciting 30 years:• the first algorithms for generating building layouts (circa 1965).• the first use of Computer graphics for building appraisal (circa 1966).• the first integrated package for building performance appraisal (circa 1972).• the first computer generated perspective drawings (circa 1973).• the first robust drafting systems (circa 1975).• the first dynamic energy models (circa 1982).• the first photorealistic colour imaging (circa 1986).• the first animations (circa 1988)• the first multimedia systems (circa 1995), and• the first convincing demonstrations of virtual reality (circa 1996).Whereas the CAAD community has been hugely inventive in the development of ICT applications to building design, it hasbeen woefully remiss in its attempts to evaluate the contribution of those developments to the quality of the built environmentor to the efficiency of the design process. In the absence of any real evidence, one can only conjecture regarding the realbenefits which fall, it is suggested, under the following headings:• Verisimilitude: The extraordinary quality of still and animated images of the formal qualities of the interiors and exteriorsof individual buildings and of whole neighborhoods must surely give great comfort to practitioners and their clients thatwhat is intended, formally, is what will be delivered, i.e. WYSIWYG - what you see is what you get.• Sustainability: The power of «first-principle» models of the dynamic energetic behaviour of buildings in response tochanging diurnal and seasonal conditions has the potential to save millions of dollars and dramatically to reduce thedamaging environmental pollution created by badly designed and managed buildings.• Productivity: CAD is now a multi-billion dollar business which offers design decision support systems which operate,effectively, across continents, time-zones, professions and companies.• Communication: Multi-media technology - cheap to deliver but high in value - is changing the way in which we canexplain and understand the past and, envisage and anticipate the future; virtual past and virtual future!MacromyopiaThe late John Lansdown offered the view, in his wonderfully prophetic way, that ...”the future will be just like the past, onlymore so...”So what can we expect the extraordinary trajectory of our subject area to be?To have any chance of being accurate we have to have an understanding of the phenomenon of macromyopia: thephenomenon exhibitted by society of greatly exaggerating the immediate short-term impact of new technologies (particularlythe information technologies) but, more importantly, seriously underestimating their sustained long-term impacts - socially,economically and intellectually . Examples of flawed predictions regarding the the future application of information technologiesinclude:• The British Government in 1880 declined to support the idea of a national telephonic system, backed by the argumentthat there were sufficient small boys in the countryside to run with messages.• Alexander Bell was modest enough to say that: «I am not boasting or exaggerating but I believe, one day, there will bea telephone in every American city».• Tom Watson, in 1943 said: «I think there is a world market for about 5 computers».• In 1977, Ken Olssop of Digital said: «There is no reason for any individuals to have a computer in their home».The FutureJust as the ascent of woman/man-kind can be attributed to her/his capacity to discover amplifiers of the modest humancapability, so we shall discover how best to exploit our most important amplifier - that of the intellect. The more we know themore we can figure; the more we can figure the more we understand; the more we understand the more we can appraise;the more we can appraise the more we can decide; the more we can decide the more we can act; the more we can act themore we can shape; and the more we can shape, the better the chance that we can leave for future generations a trulysustainable built environment which is fit-for-purpose, cost-beneficial, environmentally friendly and culturally significactCentral to this aspiration will be our understanding of the relationship between real and virtual worlds and how to moveeffortlessly between them. We need to be able to design, from within the virtual world, environments which may be real ormay remain virtual or, perhaps, be part real and part virtual.What is certain is that the next 30 years will be every bit as exciting and challenging as the first 30 years.
series	SIGRADI
email
last changed	2016/03/10 09:55

_id	7c99
authors	Maver, T.W.
year	1982
title	The Impact of Computer Based Models on Design Decision-Making
source	Chapter in Rebuild, (Ed: R Derricott et al) Wiley, 95-141
series	other
email
last changed	2003/06/02 15:00

_id	maver_102
id	maver_102
authors	Maver, Thomas W.
year	1982
title	Computer Aided Architectural Design. Implication for Practice + Education
source	Proceedings of Aicographics 82 Conference, Milano (Italy), 26/29 October, pp. 21-39
summary	Design, the highest endeavour to which man can aspire, may be defined as the activity of making explicit proposals for a change from some existing state to some future state which more closely approximates to mankind's concept of the ideal. As such, it embraces a wide spectrum of human endeavour; the outcomes of the design activity are part and parcel of our everyday life and are determinants, for better or worse, of our man-made future. In common with all complex human functions the activity of design still understood; it involves the most rational and systematic proceses of human thought and also the most intuitive conjectural leaps within the mind.
series	other
type	normal paper
email
last changed	2015/02/20 11:28

_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	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	ddssar9616
id	ddssar9616
authors	Hunt, John
year	1996
title	Establishing design directions for complex architectural projects: a decision support strategy
source	Timmermans, Harry (Ed.), Third Design and Decision Support Systems in Architecture and Urban Planning - Part one: Architecture Proceedings (Spa, Belgium), August 18-21, 1996
summary	The paper seeks to identify characteristics of the design decision-making strategy implicit in the first placed design submissions for three significant architectural competitions: the Sydney Opera House competition, and two recent design competitions for university buildings in New Zealand. Cohn Rowe's (1982) characterisation of the design process is adopted as a basis for the analysis of these case studies. Rowe's fertile analogy between design and (criminal) detection is first outlined, then brought to bear on the case studies. By means of a comparison between the successful and selected unsuccessful design submissions in each case, aspects of Rowe's characterisation of the design process are confirmed. On the basis of this analysis several common features of the competition-winning submissions, and their implicit decision-making processes, are identified. The first of these features relates to establishing project or programmatic requirements and the prioritizing of these. The second concerns the role of design parameters or requirements that appear as conflicting or contradictory, in the development of a design direction and in innovative design outcomes. The third concerns the process of simultaneous consideration given by the designer to both project parameters or requirements, and to design solution possibilities - a process described by Rowe as "dialectical interanimation".
series	DDSS
last changed	2003/08/07 16:36

_id	0107
authors	Akin, Omer and Weinel, Eleanor F. (editors)
year	1982
title	Representation and Architecture
source	v, 285 p. : ill. Silver Spring, Maryland: Information Dynamics, Inc., 1982
summary	A collection of papers developed from the proceeding of the Northeastern Regional meeting of the Association of Collegiate Schools of Architecture (ACSA), held at the Department of Architecture, Carnegie Mellon University. The introduction includes articles about representation, representation and architecture. Part 1, Who/To Whom speaks about representation and participatory design process, and of a system for recording behavior and occupying of design. Part 2, How: includes Figure, System and Memory, the Process of Design ; Representation and Creativity in Architecture and Miniature Substitutes. Part 3, With What :Information and Data Base in Design : the Computer as a Design Medium, Slides Talk and Translation
keywords	design process, representation, architecture, creativity
series	CADline
email
last changed	2003/05/17 10:09

_id	898a
authors	Bay, J.H.
year	2002
title	Cognitive Biases and Precedent Knowledge in Human and Computer-Aided Design Thinking
source	CAADRIA 2002 [Proceedings of the 7th International Conference on Computer Aided Architectural Design Research in Asia / ISBN 983-2473-42-X] Cyberjaya (Malaysia) 18–20 April 2002, pp. 213-220
doi	https://doi.org/10.52842/conf.caadria.2002.213
summary	Cognitive biases (illusions) and potential errors can occur when using precedent knowledge for analogical, pre-parametric and qualitative design thinking. This paper refers largely to part of a completed research (Bay 2001) on how heuristic biases, discussed by Tversky and Kahneman (1982) in cognitive psychology, can affect judgement and learning of facts from precedents in architectural design, made explicit using a kernel of conceptual system (Tzonis et. al., 1978) and a framework of architectural representation (Tzonis 1992). These are used here to consider how such illusions and errors may be transferred to computer aided design thinking.
series	CAADRIA
email
last changed	2022/06/07 07:54

_id	8239
authors	Campello, Ruy Eduardo and Maculan, Nelson
year	1982
title	On Deep Disjunctive Cutting Planes for Set Partitioning : A Computationally Oriented Research.
source	Pittsburgh: Design Research Center, CMU [DRC-70-11-82], 10 p.
summary	Several mathematical programming problems can be formulated as Disjunctive Programming Problems. This approach offers a powerful procedure for the generation of new and strong cutting planes with desirable properties. For general integer programs, the traditional cutting plane methodologies proved less efficient than enumerative techniques. However, for certain classes of problems, such as set partitioning, cutting planes are known to be efficient. Since the disjunctive cuts are strong, they can be expected to perform better. This paper reports on computational results with disjunctive B(.) cuts for the set partitioning problem, evaluated in terms of computer resources and other independent measures in solving specific randomly generated test problems under controlled conditions. [includes bibliography].
keywords	Mathematics, Operations Research, Integer Programming, Optimization
series	CADline
last changed	1999/02/15 15:17

_id	66df
authors	Cendes, Z.J., Minhas, F.U. and Silvester, P.P.
year	1982
title	Universal Finite Element Matrices for Tetrahedra
source	45, [22] p Pittsburgh: Design Research Center, CMU, December, 1982. DRC- 18-58-82. includes bibliography.
summary	Methods are described for forming finite element matrices for a wide variety of operators on tetrahedral finite elements, in a manner similar to that previously employed for line segments and triangles. This technique models the differentiation and product-embedding operators as rectangular matrices, and produces finite element matrices by replacing all required analytic operations by their finite matrix analogues. The method is illustrated by deriving the conventional matrix representation for Laplace's equation. Brief computer programs are given, which generate universal finite element matrices for use in various applications
keywords	mathematics, computational geometry, finite elements, analysis
series	CADline
last changed	2003/06/02 13:58

_id	89e4
authors	Cendes, Z.J., Shenton, D. and H. Shahnasser
year	1982
title	Adaptive Finite Element Mesh Generation Using the Delaunay Algorithm
source	3 p. : ill. Pittsburgh: Design Research Center, CMU, December, 1982
summary	Includes bibliography. A two-dimensional generator is described which automatically creates optimal finite element meshes using the Delaunay triangulation algorithm. The mesh generator is adaptive in the sense that elements containing the largest normalized errors are automatically refined, providing meshes with a uniform error density. The system runs on a PERQ computer made by Three Rivers Computer Company. It is menu oriented and utilizes multiple command and display windows to create and edit the object description interactively. Mesh generation from the object data base is automatic, although it may be modified interactively by the user if desired. Application of the mesh generator to electric machine design and to magnetic bubble simulation shows it to be one of the most powerful and easy to use systems yet devised
keywords	electrical engineering, triangulation, algorithms, OOPS, finite elements, analysis
series	CADline
last changed	2003/06/02 13:58

_id	cf2011_p027
id	cf2011_p027
authors	Herssens, Jasmien; Heylighen Ann
year	2011
title	A Framework of Haptic Design Parameters for Architects: Sensory Paradox Between Content and Representation
source	Computer Aided Architectural Design Futures 2011 [Proceedings of the 14th International Conference on Computer Aided Architectural Design Futures / ISBN 9782874561429] Liege (Belgium) 4-8 July 2011, pp. 685-700.
summary	Architects‚Äîlike other designers‚Äîtend to think, know and work in a visual way. In design research, this way of knowing and working is highly valued as paramount to design expertise (Cross 1982, 2006). In case of architecture, however, it is not only a particular strength, but may as well be regarded as a serious weakness. The absence of non-visual features in traditional architectural spatial representations indicates how these are disregarded as important elements in conceiving space (Dischinger 2006). This bias towards vision, and the suppression of other senses‚Äîin the way architecture is conceived, taught and critiqued‚Äîresults in a disappearance of sensory qualities (Pallasmaa 2005). Nevertheless, if architects design with more attention to non visual senses, they are able to contribute to more inclusive environments. Indeed if an environment offers a range of sensory triggers, people with different sensory capacities are able to navigate and enjoy it. Rather than implementing as many sensory triggers as possible, the intention is to make buildings and spaces accessible and enjoyable for more people, in line with the objective of inclusive design (Clarkson et al. 2007), also called Design for All or Universal Design (Ostroff 2001). Within this overall objective, the aim of our study is to develop haptic design parameters that support architects during design in paying more attention to the role of haptics, i.e. the sense of touch, in the built environment by informing them about the haptic implications of their design decisions. In the context of our study, haptic design parameters are defined as variables that can be decided upon by designers throughout the design process, and the value of which determines the haptic characteristics of the resulting design. These characteristics are based on the expertise of people who are congenitally blind, as they are more attentive to non visual information, and of professional caregivers working with them. The parameters do not intend to be prescriptive, nor to impose a particular method. Instead they seek to facilitate a more inclusive design attitude by informing designers and helping them to think differently. As the insights from the empirical studies with people born blind and caregivers have been reported elsewhere (Authors 2010), this paper starts by outlining the haptic design parameters resulting from them. Following the classification of haptics into active, dynamic and passive touch, the built environment unfolds into surfaces that can act as ‚Äúmovement‚Äù, ‚Äúguiding‚Äù and/or ‚Äúrest‚Äù plane. Furthermore design techniques are suggested to check the haptic qualities during the design process. Subsequently, the paper reports on a focus group interview/workshop with professional architects to assess the usability of the haptic design parameters for design practice. The architects were then asked to try out the parameters in the context of a concrete design project. The reactions suggest that the participating architects immediately picked up the underlying idea of the parameters, and recognized their relevance in relation to the design project at stake, but that their representation confronts us with a sensory paradox: although the parameters question the impact of the visual in architectural design, they are meant to be used by designers, who are used to think, know and work in a visual way.
keywords	blindness, design parameters, haptics, inclusive design, vision
series	CAAD Futures
email
last changed	2012/02/11 19:21

_id	e323
authors	Holtz, Neal M. and Rasdorf, William J.
year	1982
title	The Use of LISP for Computer-Aided Design Systems
source	18, [19] p. Pittsburgh: Design Research Center, Carnegie-Mellon University, April, 1982. includes bibliography
summary	It is suggested that the LISP programming language has many advantages and few disadvantages for use in developing complex engineering application programs. The paper attempts to explore that possibility by briefly explaining a few of the concepts of the language, by discussing some of the criticisms of it, and by mentioning some new developments. In summary it is suggested that LISP may currently be the best programming language to use for the development of computer- aided design (CAD) systems
keywords	LISP, CAD, systems, programming, languages, CAE, engineering
series	CADline
last changed	2003/06/02 13:58

_id	c55f
authors	Kalay, Yehuda E.
year	1986
title	The Impact of CAD On Architectural Design Education in the United States
source	Teaching and Research Experience with CAAD [4th eCAADe Conference Proceedings] Rome (Italy) 11-13 September 1986, pp. 348-355
doi	https://doi.org/10.52842/conf.ecaade.1986.348
summary	Computer-Aided Design (CAD) began to appear in schools of architecture in the United States over 15 years ago. By 1982, over 50% of all accredited schools of architecture in North America included some form of CAD in their curricula. This number has continued to steadily increase. For the most part, the use of CAD has been restricted to the few individuals working on special "CAD projects" and to the researchers developing CAD products. The reasons for this limitation have included the low availability, difficulty of use, restricted access and high cost of the CAD systems, as well as limited faculty and administrative support. Recently, however, partly due to the introduction of micro- computer CAD software, and partly due to the growing awareness of the importance of CAD in architectural education and practice, some schools have begun to introduce CAD as part of the general design curriculum.
series	eCAADe
email
last changed	2022/06/07 07:52

_id	8c27
authors	Kalay, Yehuda E.
year	1982
title	Determining the Spatial Containment of a Point in General Polyhedra
source	Computer graphics and Image Processing. 1982. vol. 19: pp. 303-334 : ill. includes bibliography. See also criticism and improvements in Orlowski, Marian
summary	Determining the inclusion of a point in volume-enclosing polyhedra (shapes) in 3D space is, in principle, the extension of the well-known problem of determining the inclusion of a point in a polygon in 2D space. However, the extra degree of freedom makes 3D point-polyhedron containment analysis much more difficult to solve than the 2D point polygon problem, mainly because of the nonsequential ordering of the shape elements, which requires global shape data to be applied for resolving special cases. Two general O(n) algorithms for solving the problem by reducing the 3D case into the solvable 2D case are presented. The first algorithm, denoted 'the projection method,' is applicable to any planar- faced polyhedron, reducing the dimensionality by employing parallel projection to generate planar images of the shape faces, together with an image of the point being tested for inclusion. The containment relationship of these images is used to increment a global parity-counter when appropriate, representing an abstraction for counting the intersections between the surface of the shape and a halfline extending from the point to infinity. An 'inside' relationship is established when the parity-count is odd. Special cases (coincidence of the halfline with edges or vertices of the shape) are resolved by eliminating the coincidental elements and re-projecting the merged faces. The second algorithm, denoted 'the intersection method,' is applicable to any well- formed shape, including curved-surfaced ones. It reduces the dimensionality by intersecting the polygonal trace of the shape surface at the plane of intersection, which is tested for containing the trace of the point in the plane, directly establishing the overall 3D containment relationship. A particular O(n) implementation of the 2D point-in-polygon inclusion algorithm, which is used for solving the problem once reduced in dimensionality, is also presented. The presentation is complemented by discussions of the problems associated with point-polyhedron relationship determination in general, and comparative analysis of the two particular algorithms presented
keywords	geometric modeling, point inclusion, polygons, polyhedra, computational geometry, algorithms, search, B-rep
series	CADline
email
last changed	2003/06/02 10:24

_id	2c13
authors	Knuth, Donald E.
year	1982
title	The Concept of a Meta-Font
source	Visible Language. Winter, 1982. vol. XVI: pp. 3-27 : ill. includes bibliography
summary	A single drawing of a single letter reveals only a small part of what was in the designer's mind when that letter was drawn. But when precise instructions are given about how to make such a drawing, the intelligence of that letter can be captured in a way that permits us to obtain an infinite variety of related letters from the same specification. Instead of merely describing a single letter, such instructions explain how that letter would change its shape if other parameters of the design were changed. Thus an entire font of letters and other symbols can be specified so that each character adapts itself to varying conditions in an appropriate way. Initial experiments with a precise language for pen motions suggest strongly that the font designer of the future should not simply design isolated alphabets; the challenge will be to explain exactly how each design should adapt itself gracefully to a wide range of changes in the specification. This paper gives examples of a meta-font and explains the changeable parameters in its design
keywords	programming, computer graphics, parametrization
series	CADline
last changed	2003/06/02 13:58

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