Castle Towers Shopping Centre in Sydney, owned by the Queensland Investment Corporation (QIC), is currently undergoing redevelopment and is set to become Australia’s second largest retail center on completion. A local surveying company, Project Surveyors, was engaged by QIC to create a survey-accurate architectural and structural Revit model of the shopping center. QIC released a USD 1 billion expansion proposal in March 2015, which included the demolition of one section of the center and refurbishing of the sections that were to be retained. In addition, it also planned to build a new extension, which would integrate a food court, specialty stores, restaurants and five high-rise towers. Once the entire project is completed, Castle Towers Shopping Centre will have a retail floor area of approximately 150,000 square meters. Project Surveyors is using a variety of laser scanners manufactured by Leica Geosystems for this project and has appointed seven qualified Laser Scanning surveyors to comply with the strict deadline for its completion.
The biggest challenge Project Surveyors faced while working on this project was the extremely strict deadline for completing the task. The company was expected to deliver the BIM model of the shopping center, after conducting a meticulous survey of the existing building that has an area of approximately 375,000 square meters, within 90 days. Various dimensional obstacles such as cascading floors, topographic level changes, and add-on buildings of diverse sizes, made the process even more difficult.
Project Surveyors decided to use a variety of solutions offered by Leica Geosystems to capture and analyze the data. Leica ScanStation C10 and P20 were selected for the majority of the surveying work. Leica ScanStation C10 served the purpose impeccably when it came to surveying from a long-range; hence it was used extensively in capturing data related to the external facade of the shopping center. It was also used indoors for large structures, such as the parking garages. However, for the major part of indoor surveying, Project Surveyors used Leica ScanStation P20, since it is highly appropriate for producing good quality and fast reliable data at a lower resolution. The fast scanning time of Leica ScanStation P20 helped them improve the site workflow by quadrupling the productivity per day.
Project Surveyors also used Leica TS15 and Leica MultiStation MS50 for the survey control phase. Leica MultiStation MS50 was used for completing specific tasks like scanning windows. All pieces of equipment played a pivotal role in establishing a survey control network around the periphery of the site and on each floor of the shopping center. In the process, these instruments ensured precision to the level of millimeters for aligning the scans of the retrofitted sections of the structure. To maintain the accuracy of the overall point clouds, laser scan targets were coordinated within the control network. Project Surveyors chose to use software solution Leica Cyclone 9.0 to clean and register these point cloud data. The auto-alignment registration feature of the software allowed them to finish the entire process of cleaning and registering the point cloud data within a matter of 20 days. This new auto-alignment feature only takes 30-60 seconds per scan, compared to the traditional point-cloud to point-cloud visual alignment that takes around two minutes for each scan. For a smaller building or a structure requiring relatively fewer scans, the traditional way works well. But when it comes to huge structures, like in this project, the new feature can help save a lot of time and enhance workflow in the long run.
Project Surveyors also used Leica TruView software to provide architects with point cloud data. This enabled the designers and architects to overlay the previously prepared laser scans in the model and have access to additional information such as precise dimensions, which in turn increased the accuracy in project planning. Not only did the Leica TruView images serve as deliverables for the client but they also helped the modeler achieve a complete understanding of the nitty-gritty of the project and its assets.
Project Surveyors decided to use BIM solutions like Autodesk Revit and Autodesk Revit MEP for preparing the survey-accurate model of the existing shopping center, aided by the laser scanned images. For modeling the architectural elements and façade, Autodesk Revit 14 was used primarily, whereas Autodesk Revit MEP was used to create pipes, plants, ducts, and other elements related to the services core of the building. Because of the strict deadline, Project Surveyors assembled a team of modelers who worked in unison on one central model across a wired and large data network. Leica Cyclone 9.0 helped the team use its export option to export the point clouds either separately as binary PTG files or unified as PTS files. These files were then converted into Autodesk-compatible RCS files, which can be used on the Revit platform using Autodesk Recap.
Project Surveyors also used Leica Cloudwork for Revit, which helped them eliminate hindrances in the workflow, including the export and conversion of files. This helped them provide modelers with point cloud conversion tools and a single master data source, rather than multiple versions of files and duplicate files to deal with.
This particular project is a prime example of innovative use of High Definition Surveying (HDS) in BIM. With the use of a variety of HDS techniques, the surveyors and the architects gained a complete understanding of the existing conditions of the structure, which gave them the ability to visualize what needed to be done to execute the proposal. It also helped the Project Surveyors’ team organize building related information across an accessible platform. It helped them provide value-added deliverables to their clients. The team was able to perform 3,700 scans on site over a period of just 55 days, which helped increase their productivity by at least 50 percent. This project secured top honors in the annual Leica Geosystems High-Definition Surveying Plan Contest in HxGN LIVE 2015 that took place in Las Vegas. A panel comprising 11 judges evaluated as many as 24 entries based on the stage of completion of the project and usefulness of their plans, the creative use of point clouds and models, and overall appearance. Project Surveyors also secured the first place in the Buildings/Heritage category.
|Location||Sydney, New South Wales, Australia|
|Client||Queensland Investment Corporation (QIC)|
|Technology partners||Leica Geosystems & Autodesk|
|Area||375,000 square meters|
|Year of Completion||2019 (First Phase)|
|Digital technologies used||BIM, Laser Scanning|
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