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

PDF papers
authors Tan, Milton
year 1990
title Saying What It Is by What It Is Like - Describing Shapes Using Line Relationships
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. 201-213
summary Shapes - taken as well-defined collections of lines - are fundamental building blocks in architectural drawings. From doodles to shop drawings, shapes are used to denote ideas and represent elements of design, many of which ultimately translate into actual objects. But because designs evolve, the shapes representing a design are seldom static - instead, they are perpetually open to transformations. And since transformations involve relationships, conventional methods of describing shapes as sets of discrete endpoints may not provide an appropriate foundation for schematic design. This paper begins with a review of the perception of shapes and its significance in design. In particular, it argues that juxtapositions and inter-relationships of shapes are important seedbeds for creative development of designs. It is clear that conventional representation of shapes as sets of discrete lines does not cope with these -emergent" subshapes; the most basic of which arise out of intersecting and colinear lines. Attempts to redress this by using ‘reduction rules’ based on traditional point-and-line data structures are encumbered by computational problems of precision and shape specification. Basically, this means that some ‘close’ cases of sub-shapes may escape detection and their specifications are difficult to use in substitution operations. The paper presents the findings of a computer project - Emergence II - which explored a 'relational' description of shapes based on the concept of construction lines. It builds on the notion that architectural shapes are constructed in a graphic context and that, at a basic compositional level, the context can be set by construction lines. Accordingly, the interface enables the delineation of line segments with reference to pre-established construction lines. This results in a simple data structure where the knowledge of shapes is centralized in a lookup table of all its construction lines rather than dispersed in the specifications of line segments. Taking this approach, the prototype software shows the ease and efficiency of applying ‘reduction rules’ for intersection and colinear conditions, and for finding emergent sub-shapes by simply tracking the construction lines delimiting the ends of line segments.
series CAAD Futures
full text file.pdf (132,904 bytes)
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100%; open Arnheim, R. (1974) Find in CUMINCAD Art and Visual Perception , University of Califomia Press, Berkeley & Los Angeles. (Originally published 1954.)

100%; open Chase, S. (1989) Find in CUMINCAD Shapes and Shape Grammars: from mathematical model to computer implementation , Environment and Planning B: Planning and Design, v16, pp. 216-242

100%; open Krishnamurti, R. and Giraud, C. (1986) Find in CUMINCAD Towards a shape editor: the implementation of a shape generation system , Environment and Planning B: Planning and Design, v13 pp. 391-404

100%; open Krishnamurti, R. (1980) Find in CUMINCAD The arithmetic of shapes , Environment and Planning B: Planning and Design, v7, pp. 463-484

100%; open Krishnamurti, R. (1981) Find in CUMINCAD The construction of shapes , Envirorument and Planning B: Planning and Design, v8 pp. 5-40

100%; open Mitchell, W., Liggett, R. and Kvan, T. (1987) Find in CUMINCAD The Art of Computer Graphics Programming , Van Nostrand Reinhold, NY

100%; open Mitchell, W., Liggett, R. and Tan, M. (1988) Find in CUMINCAD The Topdown System and its Use in Teaching - an exploration of structured, knowledge-based design , Proceedings of the Association of Computer-aided Design in Architecture Workshop 88

100%; open Mitchell, W., Liggett, R. and Tan, M. (1989) Find in CUMINCAD On Teaching Designers to Program and Programmers to Design , Proceedings of the 1989 CAAD Futures Conference. MIT Press, Cambridge, MA

100%; open Nagakura, T. (1989) Find in CUMINCAD Shape Recognition & Transformation - a Script-based Approach , Proceedings of the 1989 CAAD Futures Conference. MIT Press, Cambridge

100%; open Putnam, H. (1987) Find in CUMINCAD Many Faces of Realism , Open Court, LaSalle, Il

100%; open Stiny, G. (1989) Find in CUMINCAD What Designers Do that Computers Should , Proceedings of the 1989 CAAD Futures Conference. MIT Press, Cambridge, MA

100%; open Tan, M. (1987) Find in CUMINCAD Miesing About - a computer program to investigate parametric variation of the Project for a Brick Country House , 1923 by Mies van der Rohe. Unpublished project

100%; open Winston, P. and Horn (1989) Find in CUMINCAD LISP , Addison-Wesley, Reading, MA (3rd. edition)

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