Scan 'till you drop

When an international retail group approached the Australian surveying firm, Project Surveyors, about creating a survey-accurate architectural and structural Revit model for the country’s second largest shopping centre, the firm was excited to participate. When the deadline was set for only 90 days later, Project Surveyors knew while future centre customers may shop till they dropped, the firm’s seven qualified laser scanning surveyors would be doing the same with 3D laser scanning.

The Sydney shopping centre is currently undergoing redevelopment, and the client needed a fully-parametric Revit Building Information Modelling (BIM) model for architects, engineers and facility managers to accurately plan the work needed. Covering a space of 375,000 square metres with vari-ous dimensional obstacles, such as cascading floors, topographic level changes and add-on buildings of diverse sizes, Project Surveyors faced one of its most complex jobs in its 43-year history.

“The enormity and complicated aspects to the building meant that our surveyors had to be meticulous when documenting scan positions and on field notes to assist in the registration of scans,” said Andy Jackson, Project Surveyors’ BIM Spatial manager. “With our Leica Geosystems instruments and soft-ware, we could ensure this.”

Scanning, modelling with confidence
Project Surveyors used a variety of Leica Geosystems solutions to capture, model and analyse the data. Starting with the Leica ScanScations C10 and P20, the surveyors were able to capture minute details. The Leica ScanStation C10 was used for the external facades and inside for large structures, such as the parking garages, due to its long-range capability. Inside, the Leica ScanStation P20 was used for its quality of producing fast reliable data at low resolution.

“The fast scanning time of the P20 helped us improve site workflow, increasing the number of scans per day fourfold,” said Jackson.

For survey control, Project Surveyors used the Leica TS15 and Leica MultiStation MS50. The Multi-Station was also used to scan windows for simpler capturing. Establishing a survey control network around the perimeter of the site and throughout the shopping centre at each level, these instruments ensured millimetre precision for aligning scans of the retrofitting construction. Laser scan targets were coordinated within the control network to maintain the accuracy of the overall point clouds.

现场共有3700扫描从55天的结果ed from the project. The point clouds from these scans were cleaned and registered using Leica Cyclone 9.0. The entire process only took 20 days due to the addition of the auto-alignment registration within the software. Compared to point cloud-to-point cloud visual alignment, which would take around two minutes each to visually find common points, auto-alignment only takes 30 seconds to one minute.

“The time does not sound like much for a few scans, but when we’re talking about thousands of scans, this becomes a significant amount of time saved,” said Jackson. “With these savings, we were able to increase our productivity by at least 50 percent.”

The firm also used Leica TruView to provide the architects with the point cloud data so they could overlay in the model and have extra information, such as dimensions they needed to extract for accu-rate and realistic planning.

杰克逊说：“ Leica Truview图像是客户的可交付方式，但它们也帮助建模者完全了解了他们的建模。”

Autodesk Revit 2014 was used to model architectural elements while Autodesk Revit Mechanical, Electrical, Piping (MEP) was used to create pipes, plant, ducts and other services to create a partial MEP model of the loading docks. As the size and detail of this project would have taken one modeller 120 days to complete, Project Surveyors worked with a team of modellers in collaboration on one central model across a wired and large-data network.

使用Leica Cyclone 9.0中的导出选项，测量师分别将点云作为二进制PTG文件导出，或者统一为PTS文件。然后使用Autodesk Recap将文件转换为兼容Autodesk兼容的RCS文件，然后可以将其插入Revit并进行建模。杰克逊（Jackson）使用Leica Cloudwork进行修订，并补充说，将消除工作流程的导出和转换步骤，从而为建模者提供点云转换工具以及单个主数据源，而不是多个文件和要处理的文件版本。

“Using this laser scanning technology, we have won similar large projects, such as one in Sydney where we’re working with the same consultants who used this model as an example to the project owner of what they required as survey information,” said Scott Deveridge, Project Surveyors director. “Referrals to provide a similar service on another challenging project is the best feedback we can get.”

Lessons learned from HxGN LIVE
With attending HxGN LIVE 2014 in Las Vegas only a few months before the start of the project, Pro-ject Surveyors found the shopping centre project a valuable opportunity to put some of the lessons it learned at the international conference and exhibition to practice. Using these new ideas, the firm real-ised an approximate time savings of 75 percent.

使用扫描到扫描的注册和自动对齐，该公司减少了对每次扫描目标的依赖。测量师还使用了较低的分辨率，使扫描仪之间的扫描仪之间的运行在设置之间，并创建了轮式转移三脚架，以更快地将扫描仪重新放置。

杰克逊说：“虽然我们只能每天收集大约16次扫描，但使用我们从HXGN Live中学到的东西，我们现在可以每天收集60至80次扫描。”“我们还每小时进行大约30次扫描，是以前的两倍。这对我们来说是显着的效率提高，因此可以节省成本。”

返回2015年在拉斯维加斯举行的HXGN Live，该项目在年度Leica Geosys-Tem高清测量（HDS）计划比赛中获得了最高荣誉。由11名合格法官组成的小组根据计划的完整性和实用性，点云和模型的创造性以及整体外观评估了24个企业。项目测量师在Building/Heritage类别中获得了该项目的第一名。

“Our team has worked hard, and we are always looking for innovative ways to improve our business,” said Jackson. “Winning this award confirms our commitment to the profession and our dedication to the clients.”

A prime example
悉尼购物中心项目的另一个方面是在BIM中使用HDS的创新使用。通过在现场和办公室中使用各种HDS技术，项目测量师能够在无障碍平台上组织和协作建筑信息。

“Using laser scanning in BIM helps us to have a complete understanding of what’s already there, what needs to be done, and how well the building process took place,” said Jackson. “Using laser scanning in BIM allows us to provide value-added deliverables to our clients.”

This project is an ideal demonstration of making the real digital world. As HDS captures the most current and accurate situation, professionals can then implement that data into software programs, such as Leica Cyclone or Autodesk Recap, to produce the realistic workable models. Exact adaptions can then be made so that when work is carried out on site, intelligent information is clear and error-free.

“The technology of HDS provides the tools and workflows needed to accurately and definitively cap-ture digital assets in minutes.” said Faheem Khan, vice president, business development manager for Leica Geosystems HDS. “Being able to capture, manage and deliver information and knowledge to all stakeholders underpins our strategy to provide the fastest, cleanest and most reliable hardware as well as a software portfolio that scales for all project sizes, disciplines and users.”