When AHR surveyed the 30m high ceiling of Beverley Minster, there was no need for expensive and inconvenient scaffolding. Instead, the latest Scan to BIM technology allowed a full survey of the Gothic church’s ceiling to be undertaken from ground level.
“Scan to BIM is a game changer,” says AHR regional director Lee McDougall, who expects the technology to play a major role in opening up the application of BIM to refurbishment projects and in particular, to the heritage sector. “Slowly but surely the industry is waking up and recognizing its value,” he says, adding that AHR are one of the few design groups to invest in the technology.
AHR’s 15-strong Geomatics team has seen a massive growth in Scan to BIM work over the last 12 months, mainly through demand from external clients as well as for AHR’s own projects. These range from historic Grade A listed Waverley Station in Edinburgh, to a recent Government BIM Pathfinder project – a refurbishment for the Ministry of Justice.
As a result, its laser scanners have been kept busy, spinning 360 degrees and sending out 100,000 laser pulses per second to create the 3D points that co-ordinate the data required for BIM. These scanners, which have ranges of 150-300 metres, don’t require ambient light so can operate in the dark, often working through the night to take advantage of empty sites.
“In sensitive areas such as a prison, clients don’t want to close a wing on a regular basis. So for us to go in once and capture everything we need is very appealing,” says Lee McDougall. Images from the scans are uploaded onto the AHR Digital Portal (ADP). Each image is effectively a ball of data with a set of dimensions, coordinates, areas and perimeters accessible behind the image, all captured in the same time as would be needed for a simple plan survey.
While there are obvious speed, practicalities and health and safety advantages particularly when dealing with sensitive locations, the real gain over traditional surveying methods is the greater depth of information that Scan to BIM can provide for refurbishment projects and its ease of use for both building the BIM model and as an interactive visual resource. Clients can also decide what they want to find out retrospectively using this information, rather than at the onset of a survey. Increased client engagement through use of the ADP is another major advantage, allowing the client to interrogate any part of the model through 360 degrees.
For projects on existing buildings, a BIM model with all dimensional, materials, condition and cost information available to the whole design team can be invaluable. This technology has particular benefits for heritage sector clients such as English Heritage, for whom AHR recently surveyed the Swiss Cottage & Museum at Osborne House on the Isle of Wight using Scan to BIM. With the 3D scanning recording points just 3mm apart, the data can determine important subtleties such as tiny variations in the flushness of the walls which are particularly relevant to the owners of historic buildings.
AHR also foresee considerable gains for clients managing large property portfolios who can use it to access data and visual archives rather than making site visits. There would be valuable gains for campus or estate owners to gradually build up digital representation of their whole portfolio.
Technology is fast evolving, and there is potential for the development of self-recognition and extraction in the next ten years that would save considerable time in producing the BIM model.
“This will make information available and useful to less technically-minded people,” predicts AHR Building Consultancy director Allan Hunt, who expects a great increase in the different applications for Scan to BIM. “People will very quickly realize its benefits,” he adds.
Pamela Buxton is the current editor of BD's monthly magazine BD Reviews.