Watch a 3D flythrough of the AJ office + ScanLAB founders William Trossell and Matt Shaw explain the impact that BIM-transferable 3D ‘pointcloud’ scans will have on architecture
William Trossell and Matt Shaw of ScanLAB use revolutionary ‘pointcloud’ infrared laser scanning to create millimetre-accurate 3D models that can be imported directly into BIM. Last week the pair ‘scanned’ the AJ office at Greater London House. In this interview, the recent Bartlett graduates discuss the potential architectural uses for the technology.
How will 3D laser scanning benefit architects?
Laser scanning creates a detailed pointcloud of 3D information about a site to an unparalleled degree of accuracy. The level of site data we can collect at the start of a project can affect the subsequent design process. It provides information that can help preserve our cultural heritage, capturing a site or building before and after restoration to permanently archive its condition. The data can also be used in repairing damaged components or to check if new parts fit.
How well does it work with BIM?
Pointcloud data is now integrated into most BIM packages available on the market. This means our data fits seamlessly into Revit to help design and develop both existing buildings and new structures on specific sites. Laser scanning also allows retrofit buildings to be a far more efficient, and therefore profitable, business for architects.
How much does it cost to scan a building?
The cost of hardware is prohibitive for most architects wanting to use scanners, with the most affordable systems around £30,000. However, as a service the price has come down dramatically over the last year. Now 3D scanning is comparable to regular surveying costs and affordable for every scale of project.
For example, the cost of scanning a terraced house in London would be in the region of £1,000 to £2,000, depending on the complexity and size of the property.
How long does a scan take?
A simple scan can take a matter of hours, with the data available in CAD a few days later in enough detail to locate the exact position of every light switch, brick course and architrave detail. This makes 3D scanning comparable to standard surveying techniques in terms of cost and far advanced in terms of information.
The actual scanning process can be as quick as a 30-second scan for a full 360o survey but there is a little more time involved in processing the data and stitching multiple scans together, although advances in technology are making this faster. We aim to scan and get the data to the client within a week.
Could you scan a whole city or neighbourhood, or are there limits on scale?
Scanners typically have a range of between 120m and 450m. When you start to join scans together you can cover vast areas. We also work with mobile units that work in a similar way to Google Streetview vehicles. These collect a helix of scan data as you drive down the street, capturing detail approximately every 50mm. This can be combined with airborne laser scanners to capture data in 1km wide blocks. Eventually, 3D scan data is the way people will collect all their spatial city data.
How does your product differ from existing tools and 3D models of cities?
3D laser scanning is forensic in its detail. While existing 3D versions of cities are very useful at massing model-level, this technology has the ability to offer city models with intricate details of the urban fabric included for use and inspection.
NBS’s Stephen Hamil on point cloud surveys
On many new build projects, clients are now insisting on the use of BIM. This is utilised through the design and construction phases, and then passed to the client at hand-over. One of the big advantages to the client is in its application to facility management and the benefits are only increased when this is multiplied across a number of sites. For an owner of hundreds of buildings, having BIM digital records of exactly what materials they are made from can help maximise efficiencies in terms of running costs and renewing warranties. Such records also help manage maintenance, refurbishment and alteration work.
However, the percentage of a client’s new build work can be small in comparison to that of managing existing facilities. This is especially true in the current economic climate. Point cloud surveys are one method of generating a BIM from an existing building. Through laser technology it is possible to survey the spaces in an existing building to create a digital ‘cloud’ of geometrical points. All of this data can then be used to generate the geometry of the building. This is then imported into a BIM enabled CAD package and the materials are identified. More ‘meat on the bone’ can be added to this BIM by adding detailed specification information to these materials.
The cost of a point cloud survey is now roughly the same as a traditional 2D survey. It is extremely accurate and generates a 3D model from which unlimited 2D ‘cuts’ can be taken - so it surely is the future?
I’ve heard it said that ‘if a building is worth building it’s worth building twice, once digitally during the design process and then again physically during the construction process’. Thinking about point cloud surveys, if there are design variations during construction, is it worth ‘building’ a third time? Before hand-over the building could be surveyed to create an ‘as-built’ model that can be compared with the design model, and provide a true digital record of the building.
- Stephen Hamil is head of BIM at NBS
ScanLAB Video: The AJ office in 3D