Immersive Visualization of Building Information Models
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Design Innovation Research Centre Working Paper, Number 6 Immersive Visualization of Building Information Models Ben Dalton and Maxwell Parfitt DIRC Working Paper 6 19 September 2013 Version 1.0 Please note that this means the document is being checked and modified and is subject to change. Please do check back for later versions. Design Innovation Research Centre, University of Reading, UK www.reading.ac.uk/designinnovation [email protected] Please cite as: Dalton, B and Parfitt, M. (2013) Immersive Visualization of Building Information Models, Design Innovation Research Centre working paper 6, [version number]. Immersive Visualization of Building Information Models WP 6, v 1.0 1 Design Innovation Research Centre Working Paper, Number 6 Ben Dalton and Maxwell Parfitt, School of Construction Management and Engineering University of Reading, UK. Abstract This working paper reports on work to develop and document workflows that can be used to prepare large models for real-time immersive viewing with high-end display solutions. As Building Information Modelling (BIM) becomes more widely used in practice, construction professionals want to visualize and interact with their models, without substantial model preparation work. The gaming engine Unity3D V4.2 is explored to produce the virtual environment for visual display, and work identifies different 3D file formats that can be imported and exported. This paper compares 8 workflows that are suitable for visualising large models, from Autodesk, Bentley, Google Earth, Graphisoft, Nemetschek and Trimble products, in a 3D fully immersive CAVE. The working paper also discusses 7 key challenges, namely; intersecting vertices, data- heavy models, object nomenclature, duplication of texture-assignments, rectangular texture images, exporting two-sided materials, and inconsistent formatting. It concludes with recommendations for researchers and professionals that want to view and interact with models on high-end display equipment and visualisation systems when using the Unity3D game engine. Keywords: immersive environments, BIM, virtual reality, CAVE, workflows, Unity3D WP 6, v 1.0 2 Design Innovation Research Centre Working Paper, Number 6 Contents 1 Introduction .............................................................................................................................................................. 4 2 Method...................................................................................................................................................................... 4 2.1 Workflows ......................................................................................................................................................... 4 2.2 Equipment ......................................................................................................................................................... 5 2.3 Unity 3D ............................................................................................................................................................ 5 3 Findings ..................................................................................................................................................................... 7 3.1 Workflows ......................................................................................................................................................... 7 3.2 Challenges of large models ............................................................................................................................... 7 4 Discussion and Conclusions ...................................................................................................................................... 9 5 References ................................................................................................................................................................ 9 APPENDIX A: Using Unity ................................................................................................................................................ 10 1. Creating a new project ........................................................................................................................................ 10 2. Importing and utilising assets ............................................................................................................................. 10 4. Creating a basic scene and previewing in game mode ....................................................................................... 11 APPENDIX B: Workflows ................................................................................................................................................. 12 1. Autodesk Navisworks Manage 2014 ................................................................................................................... 12 2. Autodesk Revit 2013 ........................................................................................................................................... 13 3. Bentley Microstation V8i .................................................................................................................................... 15 4. Google Earth ....................................................................................................................................................... 16 5. Graphisoft ArchiCAD 17 ...................................................................................................................................... 17 6. Nemetschek Vectorworks 2013 .......................................................................................................................... 17 7. Trimble SketchUp Pro 2013 ................................................................................................................................ 18 8. Trimble SketchUp 2013 ....................................................................................................................................... 19 APPENDIX C: File conversion chart ................................................................................................................................. 19 WP 6, v 1.0 3 Design Innovation Research Centre Working Paper, Number 6 1 Introduction This working paper reports the output of a short study to develop new workflows to view built environment models created using standard software packages in immersive visualization environments. The research develops and extends published workflows (e.g. Penn State, 2013), which give guidance to researchers and students but shows this translation using small and moderately sized building models. Our interest is in developing stable workflows for use with datasets on the scale generated by major construction and infrastructure projects. Workflows for translating data into packages for interactive real- time 3D display are important as construction clients and project teams need new ways to visualize and interact with their data, whilst not incurring excessive latency in the conversion process. The contribution is to identify different software formats that can be imported and exported, comparison of 8 workflows that are suitable for large models, and a discussion of 7 key challenges when working with models for visualisation. The next section provides an overview of the approach and methods used. The following section provides an overview of the findings and compares workflows, indicating more detailed information about Unity3D with the individual developed workflows located in the appendices. The paper concludes with recommendations for researchers and professionals who would want to view and interact with models, in real-time, prepared using simple and fast conversion methods. 2 Method 2.1 Workflows The focus of this study is on developing workflows from file formats native to the prominent design and construction software packages: Autodesk Navisworks Manage 2014; Autodesk Revit 2013; Bentley MicroStation V8i; Graphisoft ArchiCAD 17; Nemetschek Vectorworks 2013; Trimble SketchUp Pro 2013; Trimble SketchUp 2013; and Tekla Structures 18.1. Emphasis was placed on developing short workflows which would benefit construction professionals and allow for the transfer of models into the CAVE with relative ease. Over six weeks, trials were conducted with one collaborator’s model of a large railway infrastructure project which contained over 14 million vertices. At the start the focus was on the workflow from Autodesk Revit to Unity using previously published workflows as a starting point for the translation activity; however as the infrastructure project model was provided in the Bentley DGN format this approach was quickly dropped in favour of using the native file formats. The models master file was first translated as a SKP file into SketchUp Pro as an intermediary format to then be exported into Unity as an FBX, but the export process into SketchUp was found to take more than 2 days to export. The resulting SKP file was found to be over 600Mb and extremely slow to manipulate, so the same process was then trialled using the individual subsidiary seed files which were referenced by the master DGN file, so that they could be recombined in Unity3D. Although this was a shorter process, only taking 9.5 hours, the task was significantly more complex as it required a lot of human interaction and the translated models were heavily tessellated by SketchUp. The exported model segments shared a common coordinate system which made the