Extending Model Use in Virtual Heritage: User–Centric Implementation of a Protected Remote Rendering Visualization Tool
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EXTENDING MODEL USE IN VIRTUAL HERITAGE: USER–CENTRIC IMPLEMENTATION OF A PROTECTED REMOTE RENDERING VISUALIZATION TOOL Leif Christiansen Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Doctor of Philosophy in the School of Informatics, Computing, & Engineering, Indiana University May 2019 Accepted by the Graduate Faculty, Indiana University, in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Doctoral Committee Bernard Frischer, PhD Martin A. Siegel, PhD Dimitrij Hmeljak, PhD David Crandall, PhD Date of Defense: 04/22/2019 ii Copyright © 2019 Leif Christiansen iii To all the lovely three-dimensional people in my life. iv ACKNOWLEDGEMENTS Throughout writing this dissertation I have received a bounty of support and assistance. I would first like to express my sincere thanks and gratitude to my adviser Bernard Frischer for his unflagging help and support in formulating and executing this dissertation. I would also like to thank my committee members Mitja Hmeljak, Martin Siegel, and David Crandall for their insight and guidance, with special thanks to Mitja in first introducing me to programming computer graphics. In addition, I would like to thank my fellow students Matthew Brennan, Nicholas Plank, and Matei Tichindelean for their help refining the ideas behind this work and editing the written prose. Finally, a special thanks to my family for raising me right and my beautiful partner Te’Arrow for keeping me focused and sane. v Leif Christiansen EXTENDING MODEL USE IN VIRTUAL HERITAGE: USER–CENTRIC IMPLEMENTATION OF A PROTECTED REMOTE RENDERING VISUALIZATION TOOL Virtual Heritage (VH) is the application of computing technologies, in particular, 3D graphics, to the documentation, study, preservation, and dissemination of cultural heritage. Given recent advances in both software and hardware, there has been a veritable boom in the production of 3D digital models of cultural heritage. These 3D digital models represent significant investments and stand at the intersection of claims to copyright of the digital replica and to ownership of the underlying digitized cultural property. Thus, it is understandable that creators of digital products, cultural heritage institutions, and owners of cultural property may desire to have control over the use, characteristics, and dissemination of VH models. Despite the growing prevalence of 3D digital models in VH, their role in the production of new knowledge remains to be examined in depth. This dissertation presents the design, development, and implementation of a publicly available tool for the protected visualization of high-resolution 3D VH models in a web browser. First, I survey the historical precedents for the use of 3D digital models in VH and its related fields, with special attention to the epistemological function of models. Second, current practices and needs are documented through surveys and interviews with VH scholars. Third, I present the basic visualization tool and demonstrate its security and usability. Finally, the results of the literature review, surveys, and interviews are used to design and implement a more fully featured visualization tool based on protected remote rendering, one intended to more clearly vi address the actual needs and practices of scholars in the new field of VH. Bernard Frischer, PhD Martin A. Siegel, PhD Dimitrij Hmeljak, PhD David Crandall, PhD vii TABLE OF CONTENTS Acknowledgements . v Abstract . vi List of Tables . xiv List of Figures . xvi Chapter 1: Introduction . 1 1.1 Motivation . 1 1.2 Problem Definition . 2 1.3 Key Contributions . 4 1.4 Structure of Work . 4 Chapter 2: Epistemological Value of Models . 6 2.1 Motivating Examples . 7 2.1.1 Physical Model: Pumapunku . 7 2.1.2 Non-Physical Model: Antonine Itineraries . 12 2.1.3 Dictionary Definition . 14 2.2 Trends in the Literature . 16 2.2.1 Text Bias . 17 viii 2.2.2 Material Models . 18 2.2.3 “Scientific” Fields . 20 2.3 Defining Models . 21 2.3.1 Denotation, Demonstration, and Interpretation . 21 2.3.2 The Semantic Account . 22 2.3.3 Models as Agents . 23 2.3.4 The Analogical Property Account . 24 2.4 Implications for 3D Model Use . 26 2.4.1 Validity . 27 2.4.2 Treating the Digital as Material . 28 Chapter 3: History and Technologies for 3D Model Visualization . 30 3.1 History of Model Use in the Humanities . 30 3.1.1 Plaster Casts . 31 3.1.2 Architectural Models . 35 3.2 3D in the Humanities . 37 3.2.1 A Brief Intro to 3D Computer Graphics . 37 3.2.2 3D Modeling . 39 3.2.3 File Formats . 41 3.2.4 Sharing on the Web . 45 3.3 Web3D . 46 3.3.1 VRML to WebGL . 46 3.3.2 Current State . 47 ix 3.4 Features for a VH 3D Viewer . 49 3.4.1 Technical Features . 49 3.4.2 Showing Uncertainty . 49 3.4.3 Semantic Annotation . 50 3.4.4 Exhibition, Contextualization, and Comparison . 51 3.4.5 Computational Analysis . 51 3.4.6 Security . 52 3.4.7 Accessibility . 53 3.5 Current Web Viewers in VH . 53 3.5.1 Sketchfab . 53 3.5.2 Unity . 54 3.5.3 X3DOM . 55 3.5.4 3DHOP . 56 3.5.5 Custom Viewers . 57 3.6 Future Developments for VH Viewers . 58 3.6.1 Unity Assets . 58 3.6.2 Extending Single Model Viewers . 59 3.6.3 Remote Rendering . 60 Chapter 4: Protected Remote Rendering Revisited . 61 4.1 Previous Work . 61 4.1.1 Protected Remote Rendering . 61 4.1.2 Remote Rendering . 64 x 4.1.3 Web Clients . 70 4.2 System Architecture . 72 4.2.1 Client . 75 4.2.2 Server . 79 4.2.3 Defenses . 82 4.3 Security . 86 4.3.1 Test Model . 86 4.3.2 Shape-from-Silhouette . 87 4.3.3 Shape-from-Shading . 90 4.3.4 Structure-from-Motion . 96 4.4 Performance . 102 4.4.1 Render Speed . 105 4.4.2 Time to Render . 109 4.4.3 Concurrency . 112 4.5 Conclusion and Future Work . 116 Chapter 5: Characterizing Model Use in VH . 118 5.1 Previous Work . 118 5.2 Methods . 120 5.2.1 Survey . 120 5.2.2 Interview . 122 5.3 Delineating VH Scholars . 123 5.3.1 Demographics . 123 xi 5.3.2 Position . 125 5.3.3 Technology Adoption . 129 5.3.4 Software . 133 5.3.5 Sharing and Visualization . ..