Augmented Reality Visualization of Building Information Model THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By

.............................................................................................................................. ii Acknowledgments.............................................................................................................. iii Vita ..................................................................................................................................... iv List of Figures .................................................................................................................. viii List of Table ....................................................................................................................... xi Chapter 1: Introduction ...................................................................................................... 1 Motivations...................................................................................................................... 1 Building Information Modeling and its application .................................................... 1 Advantage of Augmented Reality ............................................................................... 3 Related Works ................................................................................................................. 3 BIM System ................................................................................................................. 3 Spatial Mapping ........................................................................................................... 4 Augmented Reality Technologies ............................................................................... 5 Objectives ........................................................................................................................ 6 Chapter 2: 3D Modeling of Real World ............................................................................. 7 vi Representation of 3D Model ........................................................................................... 7 Polygonal Modeling ........................................................................................................ 9 Basic Geometry ........................................................................................................... 9 Tessellation ................................................................................................................ 10 3D Scanning Techniques ............................................................................................... 12 LiDAR Technique ..................................................................................................... 12 Structured Light Technique ....................................................................................... 15 Time of Flight Camera technique .............................................................................. 17 From Point Cloud to Meshes ..................................................................................... 18 Image-based Modeling .................................................................................................. 20 Photometric Stereo .................................................................................................... 20 Multi-view Stereo and Structure from Motion .......................................................... 23 Chapter 3: Augmented Reality System ............................................................................. 26 System Components ...................................................................................................... 26 Display ....................................................................................................................... 26 Input Device .............................................................................................................. 27 Tracking Device ........................................................................................................ 28 Image Registration Algorithm ....................................................................................... 28 Marker-based Method ................................................................................................ 28 vii Marker-less Method ................................................................................................... 30 Pose Estimation ......................................................................................................... 33 Comparing with Virtual Reality System ....................................................................... 33 Chapter 4: Augmented Reality Visualization of BIM ...................................................... 35 Basic Principles of Hololens ......................................................................................... 36 Main Components...................................................................................................... 36 Spatial Mapping and Understanding ......................................................................... 37 Building Information Model Generation....................................................................... 37 Manage Building Information Model in Unity ............................................................. 41 Model Registration and Visualization ........................................................................... 43 Main Sources of Errors ................................................................................................. 47 Chapter 5: Conclusion and Future Work .......................................................................... 52 Conclusion ..................................................................................................................... 52 Future Work .................................................................................................................. 52 References ......................................................................................................................... 54