Scan 'till you drop

当一个国际零售集团与项目测量师接触澳大利亚测量公司时，就该国第二大购物中心创建了一个调查精确的建筑和结构修订模型时，该公司很高兴参与。当截止日期仅在90天后设定时，项目测量师知道，尽管未来中心客户可能会购物直到下降，但该公司的七个合格的激光扫描测量师将通过3D激光扫描来做同样的事情。

悉尼购物中心目前正在进行重新开发，客户需要为建筑师，工程师和设施经理提供完全参数的建筑信息建模（BIM）模型，以准确地计划所需的工作。项目测量师覆盖了375,000平方米的空间，具有各种维度障碍，例如级联的地板，地形水平变化和附加建筑物的附加建筑物，在其43年的历史上面临着其最复杂的工作之一。

“在ormity 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.

为了进行调查控制，项目测量师使用了Leica TS15和Leica Multistation MS50。多站还用于扫描窗户以进行更简单的捕获。这些仪器在每个级别的周围以及整个购物中心的周围建立一个调查控制网络，这些仪器确保了毫米精度，以对齐改装构造的扫描。激光扫描靶标在控制网络中协调，以保持整体云的准确性。

从现场55天开始，总共有3,700次扫描。使用Leica Cyclone 9.0清洁并注册了这些扫描中的点云。由于软件中添加了自动对准注册，整个过程仅需20天。与点云到点云的视觉对齐相比，每次大约需要两分钟才能在视觉上找到共同点，自动对准仅需30秒至一分钟。

“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.”

该公司还使用Leica Truview为建筑师提供了点云数据，以便它们可以覆盖模型并具有额外的信息，例如他们需要提取的尺寸来提取Accu-Rate和现实计划。

杰克逊说：“ Leica Truview的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.

Using the export option in Leica Cyclone 9.0, the surveyors exported the point clouds either separately as binary ptg files or unified as pts files. Autodesk Recap was then used to convert the files into Autodesk-compatible rcs files, which could then be inserted into Revit and modelled over. Using Leica Cloudwork for Revit, Jackson added that the exportation and conversion steps of the workflow would be eliminated, providing modellers with point cloud conversion tools as well as a single master data source rather than multiple files and versions of files to deal with.

“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.

Using scan-to-scan registration and auto alignment, the firm decreased its dependence on targets for every scan. The surveyors also used a lower resolution, kept the scanner operating between setups, and created a wheeled-transport tripod to relocate the scanner faster.

“Whereas before we were only able to collect about 16 scans per day, using what we learned from HxGN LIVE, we can now collect anywhere between 60 to 80 scans per day,” said Jackson. “We are also registering about 30 scans per hour, twice as much as before. This translates into significant efficiency gains, and therefore cost savings, for us.”

Returning to HxGN LIVE 2015 in Las Vegas, the project took top honors in the annual Leica Geosys-tems High-Definition Surveying (HDS) Plan Contest. A panel of 11 qualified judges evaluated 24 en-tries based on the completeness and usefulness of the plans, the creative use of point clouds and models, and overall appearance. Project Surveyors took first place with the project in the Build-ings/Heritage category.

“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.”

一个典型的例子
Another aspect of the Sydney shopping centre project is the innovative use of HDS in BIM. Through the use of a variety of HDS techniques in the field and in the office, Project Surveyors was able to organise and collaborate building information across an accessible platform.

“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.”

该项目是建立真正的数字世界的理想演示。当HDS捕获最新和最准确的情况时，专业人员可以将这些数据实施到软件程序中，例如Leica Cyclone或Autodesk Recap，以生成现实的可行模型。然后可以进行精确的适应性，以便在现场进行工作时，智能信息清晰且没有错误。

“ HDS的技术提供了在几分钟内准确和确定的数字资产准确和确定的数字资产所需的工具和工作流程。”Leica Geosystems HDS副总裁兼业务发展经理Faheem Khan说。“能够为所有利益相关者捕获，管理和交付信息和知识的基础，以提供我们的策略，以提供最快，最清洁，最可靠的硬件以及为所有项目规模，学科和用户扩展的软件投资组合。”