DESIGN PATTERNS: AUGMENTING DESIGN PRACTICE IN PARAMETRIC CAD SYSTEMS by Zhenyu Cheryl Qian B.Arch., Southeast University, 1999 M.A.Sc., Simon Fraser University, 2004 a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the School of Interactive Arts and Technology °c Zhenyu Cheryl Qian 2009 SIMON FRASER UNIVERSITY Summer 2009 All rights reserved. This work may not be reproduced in whole or in part, by photocopy or other means, without the permission of the author. Declaration of Partial Copyright Licence The author, whose copyright is declared on the title page of this work, has granted to Simon Fraser University the right to lend this thesis, project or extended essay to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users. 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Bennett Library Simon Fraser University Burnaby, BC, Canada Last revision: Summer 2007 Abstract Parametric Computer Aided Design systems facilitate complex design activities through generating, representing, and storing parametric relations and variations in design. The systems' increasing complexity impedes the ability of designers to explore and develop their work. Pattern, as a rhetorical structure, is a generic solution to a well-described problem. I hypothesize that a designer's learning and working process in parametric modeling ap- plications can be well modeled by patterns, and making such patterns explicit can result in improved expert work practices, better learning material and support for collaborative design in parametric design environments. To achieve these goals, I designed and conducted a series of qualitative studies to search, gather, elicit, author, and communicate patterns in the context of a parametric modeling system - Bentley's GenerativeComponentsTM. Apply- ing a cognitive framework of design activities, the evaluation studies show evidence of how parametric design patterns can augment and support design practice. Keywords Design Patterns, Parametric CAD System, Cognitive Design Framework, Participant Observation, Augment Design Practice iii For my husband, Yingjie Victor Chen, who o®ered me unconditional love and support throughout the course of this dissertation. iv \Art is the imposing of a pattern on experience, and our aesthetic enjoyment is recognition of the pattern." | Alfred North Whitehead, Dialogues, 1954 v Acknowledgments I feel very fortunate to have had the guidance and support of my committee throughout this engaging PhD journey. My deepest gratitude goes to my senior supervisor, Dr. Robert Woodbury, for his excellent direction and invaluable support in the production of this work. I owe much of my success to him. I would also like to thank my other supervisors, Dr. Lyn Bartram and Dr. Alissa Antle, who provided invaluable feedback and thoughtful commen- tary throughout the research process. Their critical insights helped to strengthen my work as well as positively a±rm my approach to the research. I would like to extend my gratitude to Dr. Halil Erhan and Dr. David Week, my thesis examiners, for a challenging and thought-provoking oral examination. I thank my collaborators in the research and peers in the SIAT graduate program who o®ered their support, advice, and friendship during these past ¯ve years. I am grateful to the ¯fty-one participants in my study who shared their opinions and practices despite the pressures and time constraints of the intensive design workshops and studios. They generously allowed me to use their multimedia data in the work anonymously. Without their voluntary and enthusiastic participation in the research, the project would not have been possible. A sincere thank you goes to the people from Bentley's Generative- Components development team for their kindly support during the studies. My ¯nal appreciation goes to my family. Their love and support made the di±cult times bearable and the good times better. vi Contents Approval ii Abstract iii Dedication iv Quotation v Acknowledgments vi Contents vii List of Tables xii List of Figures xiii 1 Introduction 1 1.1 The Premise . 1 1.2 The Motivation . 2 1.3 The Questions . 3 1.4 The Structure . 3 2 Understand Design Process and Design Activity 6 2.1 Understand Design Process . 7 2.1.1 De¯nitions to Illustrate Complexity of Design . 7 2.1.2 Cognitive Frameworks to Understand Design Process . 8 2.1.3 Conclusion of Cognitive Design Frameworks . 14 vii 2.2 Understand Design Activity . 16 2.2.1 Cognitive Learning Tools . 16 2.2.2 Expertise in Scaling Up to Complexity . 18 2.2.3 Collaborative Design . 20 3 Parametric Design Systems 22 3.1 What is Parametric Design? . 22 3.2 Families of Parametric Design Systems . 24 3.3 Media E®ects of Parametric Design Systems . 25 3.3.1 Analysis Framework: Tetrad of Media E®ects . 25 3.3.2 Physically Based Modeling . 27 3.3.3 Spreadsheet Modeling . 38 3.4 Parametric CAD Systems . 45 3.4.1 A Propagation-based Modeling System: GenerativeComponentsTM .. 46 3.4.2 Parametric CAD Systems Support Design . 48 3.5 Summary . 49 4 Design Patterns 51 4.1 Origins of the Notion of Design Pattern . 51 4.2 Pattern-based Projects . 53 4.2.1 Object-Oriented Software Patterns . 53 4.2.2 Workplace Design Patterns . 53 4.2.3 Graphic User Interface Patterns . 54 4.2.4 Interaction Design Patterns . 55 4.2.5 Other Pattern-based Approaches . 55 4.3 Distinctive Characteristics of Patterns . 57 4.4 Research Questions Around Patterns . 59 5 Research Methodology 61 5.1 Research Methods Framework . 62 5.1.1 Choice of Knowledge Claims . 63 5.1.2 Choice of Research Approach . 64 5.1.3 Choice of Inquiry Strategies . 64 5.2 Strategies for Establishing Reliability and Validity . 67 viii 5.2.1 Trustworthiness . 68 5.2.2 Risks of Post-hoc Approach . 69 5.2.3 Veri¯cation Strategies . 70 5.3 Summary . 72 6 Search for Evidence of Pattern-like Phenomena 73 6.1 How do Others Recognize Importance of Patterns? . 73 6.2 Pilot Study to Investigate Pattern-like Phenomena . 74 6.2.1 Research Methods . 75 6.2.2 Role of the Researcher . 76 6.2.3 Research Subjects: Local Developers . 76 6.2.4 Data Collection . 77 6.2.5 Data Analysis . 77 6.2.6 Validity Veri¯cation . 79 6.3 Pattern-like Phenomena - Idioms of Use . 80 6.3.1 Separate Control . 80 6.3.2 Compiled Features . 83 6.3.3 Position Anchor . 85 6.3.4 Two Dimensional Collections . 87 6.4 Summary . 89 7 Gather and Elicit Pattern-like Thinking 92 7.1 How do Others Elicit Pattern-like Thinking? . 92 7.2 Participant Observation to Gather Pattern-Like Thinking . 94 7.2.1 Research Methods . 94 7.2.2 Role of the Researcher . 94 7.2.3 Settings of Four Studies . 95 7.2.4 Data Collection . 99 7.2.5 Data Analysis . 99 7.2.6 Validity Veri¯cation . 102 7.3 Pattern Themes - Idioms of Use . 104 7.3.1 Rigid Transformation . 104 7.3.2 Increment Change . 108 7.3.3 Responsive E®ects .