Speeding up BIM-reconstruction of historical building with laser scanning
Author: 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?
The reconstruction 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 obtain up-to-date as-built documentation with 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.
Historical building: 3 steps to BIM with laser scanning
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
- Reconstruction work of the project.
Field work and pre-processing: 10 times faster
With a surface of 7,000 square metres, the basement, two floors, and roof, were laser scanned during three days by 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 tool allows 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 the new construction and 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.
Many simple measurement tasks were, furthermore, solved 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
The reconstruction of this historical building is a clear example on how geospatial surveying technologies can speed up reconstruction works. Thanks to laser scanning and point cloud software, the project was completed in only three months, which is significantly faster than a traditional approach:
- Field work was completed in three working days instead of a month
- 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
- 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.