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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Reformat results as: short short into frame detailed detailed into frame

_id	8e02
authors	Brown, A.G.P. and Coenen, F.P.
year	2000
title	Spatial reasoning: improving computational efficiency
source	Automation in Construction 9 (4) (2000) pp. 361-367
summary	When spatial data is analysed the result is often very computer intensive: even by the standards of contemporary technologies, the machine power needed is great and the processing times significant. This is particularly so in 3-D and 4-D scenarios. What we describe here is a technique, which tackles this and associated problems. The technique is founded in the idea of quad-tesseral addressing; a technique, which was originally applied to the analysis of atomic structures. It is based on ideas concerning Hierarchical clustering developed in the 1960s and 1970s to improve data access time [G.M. Morton, A computer oriented geodetic database and a new technique on file sequencing, IBM Canada, 1996.], and on atomic isohedral (same shape) tiling strategies developed in the 1970s and 1980s concerned with group theory [B. Grunbaum, G.C. Shephard, Tilings and Patterns, Freeman, New York, 1987.]. The technique was first suggested as a suitable representation for GIS in the early 1980s when the two strands were brought together and a tesseral arithmetic applied [F.C. Holdroyd, The Geometry of Tiling Hierarchies, Ars Combanitoria 16B (1983) 211–244.; S.B.M. Bell, B.M. Diaz, F.C. Holroyd, M.J.J. Jackson, Spatially referenced methods of processing raster and vector data, Image and Vision Computing 1 (4) (1983) 211–220.; Diaz, S.B.M. Bell, Spatial Data Processing Using Tesseral Methods, Natural Environment Research Council, Swindon, 1986.]. Here, we describe how that technique can equally be applied to the analysis of environmental interaction with built forms. The way in which the technique deals with the problems described is first to linearise the three-dimensional (3-D) space being investigated. Then, the reasoning applied to that space is applied within the same environment as the definition of the problem data. We show, with an illustrative example, how the technique can be applied. The problem then remains of how to visualise the results of the analysis so undertaken. We show how this has been accomplished so that the 3-D space and the results are represented in a way which facilitates rapid interpretation of the analysis, which has been carried out.
series	journal paper
more	http://www.elsevier.com/locate/autcon
last changed	2003/05/15 21:22

_id	5509
authors	Koutamanis, Alexandros
year	1990
title	Development of a computerized handbook of architectural plans
source	Delft University of Technology
summary	The dissertation investigates an approach to the development of visual / spatial computer representations for architectural purposes through the development of the computerized handbook of architectural plans (chap), a knowledge-based computer system capable of recognizing the metric properties of architectural plans. This investigation can be summarized as an introduction of computer vision to the computerization of architectural representations: chap represents an attempt to automate recognition of the most essential among conventional architectural drawings, floor plans. The system accepts as input digitized images of architectural plans and recognizes their spatial primitives (locations) and their spatial articulation on a variety of abstraction levels. The final output of chap is a description of the plan in terms of the grouping formations detected in its spatial articulation. The overall structure of the description is based on an analysis of its conformity to the formal rules of its “stylistic” context (which in the initial version of chap is classical architecture). Chapter 1 suggests that the poor performance of computerized architectural drawing and design systems is among others evidence of the necessity to computerize visual / spatial architectural representations. A recognition system such as chap offers comprehensive means for the investigation of a methodology for the development and use of such representations. Chapter 2 describes a fundamental task of chap: recognition of the position and shape of locations, the atomic parts of the description of an architectural plan in chap. This operation represents the final and most significant part of the first stage in processing an image input in machine environment. Chapter 3 moves to the next significant problem, recognition of the spatial arrangement of locations in an architectural plan, that is, recognition of grouping relationships that determine the subdivision of a plan into parts. In the absence of systematic and exhaustive typologic studies of classical architecture that would allow us to define a repertory of the location group types possible in classical architectural plans, Chapter 3 follows a bottom-up approach based on grouping relationships derived from elementary architectural knowledge and formalized with assistance from Gestalt theory and its antecedents. The grouping process described in Chapter 3 corresponds both in purpose and in structure to the derivation of a description of an image in computer vision [Marr 1982]. Chapter 4 investigates the well-formedness of the description of a classical architectural plan in an analytical manner: each relevant level (or sublevel) of the classical canon according to Tzonis & Lefaivre [1986] is transformed into a single group of criteria of well-formedness which is investigated independently. The hierarchical structure of the classical canon determines the coordination of these criteria into a sequence of cognitive filters which progressively analyses the correspondence of the descriptions derived as in Chapter 3 to the constraints of the canon. The methodology and techniques presented in the dissertation are primarily considered with respect to chap, a specific recognition system. The resulting specification of chap gives a measure of the use of such a system within the context of a computerized collection of architectural precedents and also presents several extensions to other areas of architecture. Although these extensions are not considered as verifiable claims, Chapter 5 describes some of their implications, including on the role of architectural drawing in computerized design systems, on architectural typologies, and on the nature and structure of generative systems in architecture.
series	thesis:PhD
email
last changed	2003/02/12 22:37

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

_id	a241
authors	Freund, Dwight D.
year	1986
title	A Note : An Interactive Procedure for Constructing Line and Circle Tangencies
source	IEEE Computer Graphics and Applications. April, 1986. vol. 6: pp. 59-63 : ill. includes bibliography
summary	This note describes a procedure that enables a designer or draftsperson with limited mathematical training to discover interactively the construction of a wide variety of tangency and intersection problems. Requiring very little code to implement, it supplements the standard tangency constructions available on commercial turnkey computer-aided-design systems with a flexibility unavailable even through the inclusion of the numerous special-purpose algorithms available in the literature
keywords	drawings, circles, computational geometry, user interface
series	CADline
last changed	2003/06/02 10:24

_id	678e
authors	Aish, Robert
year	1986
title	Three-dimensional Input and Visualization
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 68-84
summary	The aim of this chapter is to investigate techniques by which man-computer interaction could be improved, specifically in the context of architectural applications of CAD. In this application the object being designed is often an assembly of defined components. Even if the building is not actually fabricated from such components, it is usually conceptualized in these terms. In a conventional graphics- based CAD system these components are usually represented by graphical icons which are displayed on the graphics screen and arranged by the user. The system described here consists of three- dimensional modelling elements which the user physically assembles to form his design. Unlike conventional architectural models which are static (i.e. cannot be changed by the users) and passive (i.e. cannot be read by a CAD system), this model is both 'user generated' and 'machine readable'. The user can create, edit and view the model by simple, natural modelling activities and without the need to learn complex operating commands often associated with CAD systems. In particular, the user can view the model, altering his viewpoint and focus of attention in a completely natural way. Conventional computer graphics within an associated CAD system are used to represent the detailed geometry which the different three-dimensional icons may represent. In addition, computer graphics are also used to present the output of the performance attributes of the objects being modelled. In the architectural application described in this chapter an energy- balance evaluation is displayed for a building designed using the modelling device. While this system is not intended to offer a completely free-form input facility it can be considered to be a specialist man-machine interface of particular relevance to architects or engineers.
series	CAAD Futures
email
last changed	2003/11/21 15:15

_id	sigradi2008_175
id	sigradi2008_175
authors	Knight, Terry; Larry Sass, Kenfield Griffith, Ayodh Vasant Kamath
year	2008
title	Visual-Physical Grammars
source	SIGraDi 2008 - [Proceedings of the 12th Iberoamerican Congress of Digital Graphics] La Habana - Cuba 1-5 December 2008
summary	This paper introduces new visual-physical design grammars for the design and manufacture of building assembly systems that provide visually rich, culturally resonant design variations for housing. The building systems are intended to be tailored for particular cultures and communities by incorporating vernacular, decorative design into the assembly design. Two complementary areas of computational design research are brought together in this work: shape grammars and digital fabrication. The visual or graphic aspects of the research are explored through shape grammars. The physical design and manufacturing aspects are explored through advanced digital design and fabrication technologies and, in particular, build on recent work on mono-material assemblies with interlocking components that can be fabricated with CNC machines and assembled easily by hand on-site (Sass, 2007). This paper describes the initial, proof-of-concept stage of this work: the development of an automated, visual-physical grammar for an assembly system based on a vernacular language of Greek meander designs. A shape grammar for the two-dimensional Greek meander language (Knight, 1986) was translated into a three-dimensional assembly system. The components of the system are uniquely designed, concrete “meander bricks” (Figure 1). The components have integrated alignment features so that they can be easily fitted and locked together manually without binding materials. Components interlock horizontally to form courses, and courses interlock vertically in different ways to produce a visual variety of meander walls. The assembly components were prototyped at desktop scale with a layered manufacturing machine to test their appearance after assembly and their potential for design variations (Figure 2). Components were then evaluated as full-scale concrete objects for satisfaction of physical constraints related to concrete forming and component strength. The automated grammar (computer program) for this system generates assembly design variations with complete CAD/CAM data for fabrication of components formed from layered, CNC cut molds. Using the grammar, a full-scale mockup of a corner wall section was constructed to assess the structural, material, and aesthetic feasibility of the system, as well as ease of assembly. The results of this study demonstrate clearly the potentials for embedding visual properties in structural systems. They provide the foundations for further work on assembly systems for complete houses and other small-scale structures, and grammars to generate them. In the long-term, this research will lead to new solutions for economical, easily manufactured housing which is especially critical in developing countries and for post-disaster environments. These new housing solutions will not only provide shelter but will also support important cultural values through the integration of familiar visual design features. The use of inexpensive, portable digital design and fabrication technologies will allow local communities to be active, cooperative participants in the design and construction of their homes. Beyond the specific context of housing, visual-physical grammars have the potential to positively impact design and manufacture of designed artifacts at many scales, and in many domains, particularly for artifacts where visual aesthetics need to be considered jointly with physical or material requirements and design customization or variation is important.
keywords	Shape grammar, digital fabrication, building assembly, mass customization, housing
series	SIGRADI
email
last changed	2016/03/10 09:54

_id	ae5f
authors	Krishnamurti, Ramesh
year	1986
title	Modelling Design Descriptions
source	January, 1986. [5] p. : ill
summary	This paper reports some of the principles that underlie a modelling environment being developed at EdCAAD. It describes research that is part of a larger programme directed at computer-based systems that can accommodate the idiosyncratic nature of design practice, without prescriptions to the form or content of designs. That is, towards developing systems to assist in the design process by enabling designers -via conversations with the machine - to make 'reasonable' statements about design objects; to ask 'reasonable' questions about these objects; and to perform 'reasonable' tasks on these objects. Implicit in the authors' approach is the view that designing is an activity dependent on designers' perceptions of design tasks and their resolution. In the context of computer-aided design, this view of design demands that the crucial element in any machine environment lies in the ability of the machine to accept (partial) descriptions of design objects. Moreover, these descriptions can be manipulated according to some (perhaps unanticipated) criteria that the designer may wish to apply. The authors present a model for intentional descriptions of objects. That is, a description that can be structures so that it can be used to recognize objects and can be compared with other descriptions. Such a description of an object should be organized around entities with associated descriptions, it must be able to represent partial knowledge about an object, and it must accommodate multiple descriptors which can describe the object from different viewpoints. Last, but not least, these descriptions should possess a quality of 'truth' in that they reflect the (factual or otherwise) beliefs held by the designer. One way to treat these descriptions is to regard them as statements that belong to some logical framework
keywords	design process, representation, intentionallity
series	CADline
last changed	1999/02/12 15:08

_id	6916
authors	Gasparski, W.
year	1986
title	Design Methodology: How I Understand and Develop it
source	Computer-Aided Architectural Design Futures [CAAD Futures Conference Proceedings / ISBN 0-408-05300-3] Delft (The Netherlands), 18-19 September 1985, pp. 16-27
summary	The term 'methodology' is sometimes given two diametrically opposed meanings, well characterized by Mark Blaug in the preface of a very informative book devoted to the methodology of economics. This is also the case with the methodology of design. One can find studies in which 'the methodology of design' is simply a method or methods of design, given a fancy name to make it or them appear more scientific. Authors of such studies should not confuse their readers by taking methodological studies to mean technicalities of design or demanding that their interpretation and assessment of so-called 'practical applicability' should follow this criterion. The methodology of design - as we understand it has parallels in the methodology of Blaug's economics, the philosophy of practical science, the applied sciences or the sciences of artificial objects or artefacts. Understood this way, the methodology of design is neither the method of practising design nor an instruction for its use but a theoretical reflection - in the meaning given to methodology by the philosophy of science - of design. In this connection a study of the methodology of design should be provided with the subtitle, 'How researchers of practical sciences and designers understand the concept of changes'.
series	CAAD Futures
last changed	1999/04/03 17:58

_id	81ae
authors	Rasdorf, William J. and Parks, Linda M.
year	1986
title	Expert Systems and Engineering Design Knowledge
source	Electronic Computation Conference Proceedings (9th : 1986 : Birmingham, AL) American Society of Civil Engineers, pp. 28-42. CADLINE has abstract only.
summary	Of all the contributions of artificial intelligence (AI), expert systems show some of the most significant promise for engineering applications. An expert system provides a framework for acquiring, representing, and using knowledge about a particular application's domain. The role of knowledge in engineering design merits closer attention so that AI-oriented computer-aided engineering (CAE) systems can be developed and maintained systematically. Because 'knowledge' in engineering applications is loosely defined, it is necessary to identify knowledge types and the correlations between them before widespread engineering design applications can be achieved. The types of domain knowledge; facts, procedures, judgments, and control; differ from the classes of that knowledge; creative, innovative, and routine. Feasible engineering tasks for expert systems can be determined based on these types and classes of knowledge. Prototype expert systems have been developed for civil engineering applications to assist with interpretation, design, planning, diagnosis, control, and other engineering system functions. A number of these are described herein. Interpretive tasks require reasoning about a task in light of the knowledge available, while generative tasks create potential solutions to be tested against constraints. Only after classifying the domain by type and level can the engineer select an appropriate knowledge-engineering tool for the domain being considered. The critical features to be weighed after problem classification are knowledge representation techniques, control strategies, interface requirements, compatibility with traditional systems, and economic considerations. After considering all of these factors in the selection of the expert system took, the engineer can then proceed with the acquisition of knowledge and the construction and use of the expert system
keywords	design, knowledge, civil engineering, expert systems
series	CADline
last changed	2003/06/02 13:58

_id	04dd
authors	Zozaya-Gorostiza and Hendrickson, Carlos and Chris
year	1986
title	A Network Representation and Algorithm for Task Planning
source	23 p. : ill Pittsburgh, PA: Engineering Design Research Center CMU, December, 1986. EDRC-12-08-87. includes bibliography.
summary	An activity planning algorithm based on a network representations of conditions and actions is presented. The algorithm performs backward expansions on each desired condition in order to express them as a combination of initial conditions and actions. A global problem network of actions and conditions is used to represent the history of successful conditions expansions. This representation maintains consistency and improves the efficiency of search procedure. Interpretation of this problem network leads to an actions network from which feasible plans are directly obtained. The network algorithm was implemented in LISP and is applied here to solve blockworld problems similar to those found in the artificial intelligence planning literature. However, the algorithm and the network representation are general and intended to be used as an analytical tool in planning systems that formulate sequences of multiple actions
keywords	algorithms, planning, networks, representation, AI
series	CADline
last changed	2003/06/02 13:58

_id	4c79
authors	Aguilar, Lorenzo
year	1986
title	A Format for a Graphical Communications Protocol
source	IEEE Computer Graphics and Applications vol. 6.no. 3 (March, 1986): pp. 52-62
summary	This article describes the requirements for a graphical format on which a graphical on-line communications protocol can be based. It is argued that on-line graphical communications is similar to graphical session capture, and thus the author proposes an interactive graphical communications format using the GKSM session metafile. The discussion includes items that complement the GKSM metafile such as a format for on-line interactive exchange. One key application area of such a format is multimedia on-line conferencing. Therefore, a conferencing software architecture for processing the proposed format is presented. This format specification is made available to those planning multimedia conferencing systems
keywords	user interface, communication, computer graphics, multimedia, standards
series	CADline
last changed	1999/02/12 15:07

_id	242d
authors	Atkin, Brian L. and Gill, E. Moira
year	1986
title	CAD and Management of Construction Projects
source	Journal of Construction Engineering and Management, Vol. 112, December, pp. 557-565
summary	The increasing interest in computer-aided design (CAD) has prompted research that is aimed at identifying the opportunities for construction managers and building contractors. It has been found that the use of CAD systems in the U.K. is mainly confined to the production of detailed drawings. Indeed, most of the systems used are 2-D drafting tools and incapable of supporting the integration of even modest amounts of nongraphical (construction) data. On the other hand, many 3-D modeling systems have the potential to integrate construction data, although they appear to be almostignored. The use of 3-D modeling systems is considered to be the most suitable vehicle for successfully integrating these data. However, this is likely to necessitate the introduction of separate databases, preferably of the relational type. The use of 3-D modeling systems in assessing the construction implications of outline designs also presents interesting possibilities and is discussed.
series	journal paper
last changed	2003/04/23 15:14

_id	ed51
authors	Bergeron, Philippe
year	1986
title	A General Version of Crow's Shadow Volumes
source	IEEE Computer Graphics and Applications September, 1986. vol. 6: pp. 17-28 : col. ill. includes bibliography.
summary	In 1977 Frank Crow introduced a new class of algorithms for the generation of shadows. His technique, based on the concept of shadow volumes, assumes a polygonal database and a constrained environment. For example, polyhedrons must be closed, and polygons must be planar. This article presents a new version of Crow's algorithm, developed at the Universite de Montreal, which attempts a less constrained environment. The method has allowed the handling of both open and closed models and nonplanar polygons with the viewpoint anywhere, including any shadow volume. It does not, however, sacrifice the essential features of Crow's original version: penetration between polygons is allowed, and any number of light sources can be defined anywhere in 3D space, including the view volume and any shadow volume. The method has been used successfully in the film Tony de Peltrie and is easily incorporated into an existing scan-line, hidden-surface algorithm
keywords	algorithms, shadowing, polygons, computer graphics
series	CADline
last changed	1999/02/12 15:07

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

_id	caadria2007_659
id	caadria2007_659
authors	Chen, Zi-Ru
year	2007
title	The Combination of Design Media and Design Creativity _ Conventional and Digital Media
doi	https://doi.org/10.52842/conf.caadria.2007.x.w5x
source	CAADRIA 2007 [Proceedings of the 12th International Conference on Computer Aided Architectural Design Research in Asia] Nanjing (China) 19-21 April 2007
summary	Creativity is always interested in many fields, in particular, creativity and design creativity have many interpretations (Boden, 1991; Gero and Maher, 1992, 1993; Kim, 1990; Sternberg, 1988; Weisberg, 1986). In early conceptual design process, designers used large number of sketches and drawings (Purcell and Gero, 1998). The sketch can inspire the designer to increase the creativity of the designer’s creations(Schenk, 1991; Goldschmidt, 1994; Suwa and Tversky, 1997). The freehand sketches by conventional media have been believed to play important roles in processes of the creative design thinking(Goldschmidt, 1991; Schon and Wiggins, 1992; Goel, 1995; Suwa et al., 2000; Verstijnen et al., 1998; Elsas van and Vergeest, 1998). Recently, there are many researches on inspiration of the design creativity by digital media(Liu, 2001; Sasada, 1999). The digital media have been used to apply the creative activities and that caused the occurrenssce of unexpected discovery in early design processes(Gero and Maher, 1993; Mitchell, 1993; Schmitt, 1994; Gero, 1996, 2000; Coyne and Subrahmanian, 1993; Boden, 1998; Huang, 2001; Chen, 2001; Manolya et al. 1998; Verstijinen et al., 1998; Lynn, 2001). In addition, there are many applications by combination of conventional and digital media in the sketches conceptual process. However, previous works only discussed that the individual media were related to the design creativity. The cognitive research about the application of conceptual sketches design by integrating both conventional and digital media simultaneously is absent.
series	CAADRIA
email
last changed	2022/06/07 07:50

_id	4e59
authors	Koparkar, P. A. and Mudur, S.P.
year	1986
title	Generation of Continuous Smooth Curves Resulting from Operations on Parametric Surface Patches
source	Computer Aided Design. May, 1986. pp. 193-206 : ill. includes bibliography
summary	In recent years a number of techniques based on the subdivision principle have been suggested for detecting the curves resulting from the intersection of two parametrically defined surface patches. Silhouette curves of surfaces can also be detected using analogous techniques. Usually the output is a set of pixels or line segments which form the complete curve, though not necessarily in an ordered manner. This paper presents data structures for maintaining the result of subdivision, and algorithms for tracing the curves in a continuous fashion. Using a few iterations of the Newton-Raphson technique the curve points may be refined to any required precision. For each point on the curve the nonlinear equations are chosen by looking at the local topological nature of the curve so as to guarantee convergence of the Newton-Raphson technique in one or two iterations
keywords	curved surfaces, parametrization, curves, intersection, relaxation, geometric modeling, computational geometry
series	CADline
last changed	2003/06/02 14:41

_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	28d8
authors	Sarnak, Neil and Tarjan, Robert E.
year	1986
title	Planar Point Location Using Persistent Search Trees
source	Communications of the ACM July, 1986. vol. 29: pp. 669-679 : ill. includes bibliography.
summary	A classical problem in computational geometry is the planar point location problem. This problem calls for preprocessing a polygonal subdivision of the plane defined by n line segments so that, given a sequence of points, the polygon containing each point can be determined quickly on-line. Several ways of solving this problem in O(log n) query time and O(n) space are known, but they are all rather complicated. The authors propose a simple O(log n) query-time, O(n) space solution, using persistent search trees. A persistent search tree differs from an ordinary search tree in that after an insertion or deletion, the old version of the tree can stillÔ h)000*°° ÔŒ be accessed. A persistent form of binary search tree that supports insertions and deletions in the present and queries in the past is developed. The time per query or update is O(log m), where m is the total number of updates, and the space needed is O(1) per update. The planar point location algorithm is an immediate application of this data structure. The structure also provides an alternative to Chazelle's 'hive graph' structure, which has a variety of applications in geometric retrieval
keywords	search, data structures, algorithms, point inclusion, computational geometry
series	CADline
last changed	2003/06/02 13:58

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

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

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