Speeding up BIM-reconstruction of historical building with laser scanning

作者：Mikhail Anikushkin, Sergey Kotelnikov

It is challenging to meet quality requirements for reconstruction and modernisation of complex buildings projects. The more complex the building, the more time architects spend measuring. Manual measurements are, moreover, usually inaccurate and incomplete if access to certain parts of the structure is difficult to reach.

But, is there a better way to measure and obtain up-to-date as-built documentation?

Thereconstruction of a 100-year-old historical building, located in the centre of Moscow, would have been a long and winding road if real estate developer, KR Properties, had not turned to 3D laser scanning experts at Trimetari Consulting. The laser scanning firm was able to obtainup-to-date as-built documentationwith point cloud data, creating 3D models that allowed the reconstruction of a neglected two-storied building, with a former wine store on the first floor and wine stock in the basement, into exclusive loft-apartments.

历史建筑：通过激光扫描的3个步骤

Architecture and engineering bureau Alllevels, the general reconstruction designer, noticed the basement floor of the historical building has a complex layout, and walls are uneven and deviated from the vertical. With Building Information Modelling (BIM) experience since 2013, Alllevels choose laser scanning as an effective measurement tool and Trimetari Consulting LLC as a service provider.

The project has been implemented in three steps:

• Laser scanning of the building
• Data processing to obtain a 3D BIM model and panoramas
• 项目的重建工作。

Field work and pre-processing: 10 times faster

With a surface of7,000平方米, the basement, two floors, and roof, werelaser scanned during three daysby two terrestrial laser scanners. The Leica ScanStation P20 was an excellent solution thanks to high speed, accuracy and panoramic images. According to the architects’ calculations, traditional measurements would have taken at least a month.

After Leica Cyclone REGISTER, software for registering and georeferencing laser scan data to a common coordinate system, data were exported both as spherical panoramas to Leica TruView and as coloured point clouds to Autodesk design software packages.

3D model for designers TruView panoramas for engineers and team

The first and most important task for data processing is to get an actual as-built model of the building in Autodesk Revit. To accelerate the process, Leica CloudWorx for Revit plug-in was used to automate the structures modelling, and efficiently visualise and create BIM models from large point cloud data sets, creating 2D and 3D drawings with Autodesk Revit.

Point clouds and as-builts model allow to calculate reconstruction works costs. For the reconstruction in Autodesk Revit, a very useful stage toolallows to specify in the project the key stages of the work and to link the erection and demolition of objects to them. A complete BIM model of all types of works is, thus, formed in one file with exact documentation and specifications. All the constructed objects are created on thenew constructionand all existing objects receive the stage of existing, and, if necessary, demolition can be indicated. This makes it possible not only to document different stages, but also to receive specifications and three-dimensional views with any element display settings.

许多简单的测量任务,此外,年代olved by using only spherical panoramas in TruView. The software to access, view, analyse and collaborate using digital reality data was especially useful for analysing existing utilities located in the basement.

“It was the first reconstruction project, in my practice, that does not require any additional final measurement. If we need something, it was enough to open TruView or use the point cloud. No need to go onsite more than one time,”said Alexander Sokolov, main architect of Alllevels bureau.

The software allows to view panoramas from any laser scanner, make measurements and insert annotations, simplifying interaction with the customer and teamwork. Engineers can look and measure in detail using spherical panoramas in the office, significantly reducing labour costs.

New time schedule for reconstruction with laser scanning

这座历史建筑的重建是一个明显的例子，说明地理空间测量技术如何加快重建的作用。多亏了激光扫描和点云软件，project was completed in only three months, which is significantly faster than a traditional approach:

• 现场工作是在三个工作日内完成的，而不是一个月
• 3D model creation took 30 days instead of three months
• Design was completed in two months instead of four months.

The final stage of data processing and the creation of drawings and models, is a long time-consuming process, especially if additional measurements and recalculations are required. These problems are solved by laser scanning, allowing not only to automate the measurement process, but also to provide the output data in an appropriate format.

Laser scanning is the most suitable technology for designers and architects, offering the following advantages:

• Accuracy and level of detail
• Speed
• High automation during the field work
• Strong interaction with CAD environment.

A BIM reconstruction and modernisation project, based on laser scanning data, is not only fast and accurate, but also enables a new level of design workflow and interaction between all project stakeholders.