These THI updates are like buses wait 2-3 weeks and three show up at once! Still – I suppose I should be grateful to have news to report! There should be another two blog posts coming in the next week or so after a January that has been fairly quiet in terms of THI news.
On 29 January 2014 we held the second ever training event of the Prescot THI, following the two day Repair and Maintenance Course we held in December. This second training event was a ‘Laser Scanning Experience Day’ that was held at 13-15 Atherton Street.
Most of the LJMU students on the Experience Day standing outside 13-15 Atherton Street
This particular building was granted outline THI grant approval in October 2013 to bring the building back into full use and to repair it. The event counted as the project’s contribution to achieving the training and up-skilling outputs of the THI. We will be asking the people behind each grant-aided THI project to use the works as an opportunity for people to learn about working with historic buildings.
The day was organised and run by the building surveyors already working on the project – Jubb and Jubb Ltd. The Director, Lynda Jubb is Chairman of the RICS Building Conservation Forum, Director of the Register of Architects Accredited in Building Conservation and a member of the Governing Council of the RICS. So how she found the time to set up and deliver the day’s training on top of all that I’ll never know!
We had a total of 18 people attending. These were in the main final year Building Surveying students from Liverpool John Moores University, with a sprinkling of building surveyors. The high take-up of places from the University meant we didn’t need advertise places widely to fill the available places, but it was such a success that no doubt we’ll be holding similar events over the lifetime of the THI.
Laser scanners are becoming increasingly commonly used by building surveyors, particularly when working with historic buildings and archaeology. A laser scanner is a small but expensive device that sits on top of a tripod. You tell it where it is, where you want it to scan and away it goes (but it’s more complicated than that!).
These machines can do a 360-degree scan of a room in a matter of minutes. What happens is the scanner sends out a floor-to-ceiling laser beam. It calculates how far walls windows, doorways etc are by recording how long it takes the laser beam to reflect off the wall, window or doorway and return to the scanner, and hence how far away it is from the scanner. As it spins through 360-degrees, the scanner uses millions upon millions of measurements to record the dimensions of a room or space. This data can be used to create a scale 3D model of the room or space.
The scanners are accurate to a within a couple of millimetres, so they can pick up tiny details like a decorative cast iron fireplace or dainty mouldings to a ceiling and reproduce them to scale. As well as surveying buildings they are also used to scan crime and accident scenes – a quick scan can build up an invaluable highly accurate record of where everything was after the accident or crime before the wreckage or evidence is removed.
Laser scanning demonstration The scanner is the light green box of tricks on the tripod on the left of the photo. Here, the scan has been transferred onto a laptop and everyone’s gathered round for a look.
You can imagine if you had to survey a big building with lots of rooms, a large space like a concert hall or a room with lots of historic features and details, it would take an absolute age to go around and measure everything and with the best will in the world they would not be as accurate as the scanner.
Once you’ve got your data from the scanner you can do what you want with it – make simple plan and elevation drawings or go to town and spend a month making a fully interactive rendered 3D model like this one of Little Moreton Hall.
The Experience Day
On the experience day everyone was split into three small groups on different floors of 13-15 Atherton Street. Everyone was told how the scanners worked by David Langton from M & P Survey Equipment Ltd, and even given a go to run one of the machines themselves at the practical demonstration led by John Velnoweth of James Brennan Associates.
Everyone also had a go at surveying a room themselves using more ‘traditional’ hand measuring – taking measurements and plotting these on a drawn floor plan of the room. This was led by Lynda Jubb of Jubb and Jubb Ltd. I say ‘traditional’ hand measuring, but this involves laser measurers called “disto’s” that operate in the same way as the big posh 3D scanners – it calculates how far away something is by how long it took for a laser beam to bounce back.
The 3D laser scanners are still a bit of a niche in the surveying world so most people at 13-15 Atherton Street had never seen one in operation before. Similarly the LJMU students really rose to the challenge of doing practical survey work – for many of them it was the first time working on a ‘live’ building project.
For me, it shed a light (laser beam?) on how all those detailed drawings and 3D models are put together, and what kit has surveyor has at their disposal. Good to see they still use pencil and paper, but think I only saw one tape measure all day!