LA Surveys: reducing time and costs while increasing accuracy

In late 2019, during one of Lees Associates’ weekly team meetings, every project reported an issue with their original survey. Issues with surveys often only come to light months after the survey, by when their impact is inevitably greater. It was a lightbulb moment: why don’t we do them ourselves?! And so, with expertise honed over 40 years, Lees Associates decided to establish our own in-house surveying arm, and LA Surveys was born. We completed our first survey in early 2020 and haven’t looked back since.

Now, by surveying all of our projects in-house, we can offer incredible value to our clients, reducing time and costs at the front end of projects. But we don’t only survey our own projects; we offer it as a standalone service too.

We utilise the latest technology to scan buildings in 3D with an incredible degree of accuracy. From these scans we can build a detailed BIM model, from which a full suite of 2D drawings can be generated.

How does it work?

Each scan we take measures the x,y and z coordinates, as well as colour, of thousands of millimetre points across all of the surfaces of the area being scanned. When viewed in a digital 3D environment, these points can resemble a “cloud” of data, hence the term “Point Cloud” to describe this method of scanning. 

A typical point cloud, cutting through the property and showing external context

A typical survey might need anywhere between 50 and 100 scans to capture all surfaces, inside and out, of a property, each of these scans recording separate data. Our software intelligently identifies common datasets between scans and automatically stitches overlapping scans into one complete point cloud model, erasing the duplicated data to minimise file size. The stitching process is closely monitored and checked by our expert team to guarantee the quality and accuracy of the model. 

The “registration” process of stitching the data together, room by room

At the same time, our scanner is capable of taking a 360º panoramic photo at each scan location. These photos are stitched together in a similar way and allow us, while we build the model, and anyone else in the future, to explore every inch of the property without ever having to go there in person. This photogrammetry (literally “measurable photos”) is backed up by the point cloud data and allows us, or any other authorised user, to accurately measure any element in the image. Similarly, annotations can be added, which is a very useful tool for collaborative working.

The photographic data can also be extremely helpful further down the road during construction when it might be necessary to look back at an original element that might have been removed in the meantime, especially for heritage buildings.

But it is not just existing buildings that we record photogrammetry of. Our scanners can record the status of a project at any moment in time once it is under construction. For example, if there is a change of contractor it can record the as-built condition at the moment of handover.

Once we have collected the point cloud and photographic data – usually one or two days on site – it is uploaded to an online platform from where it be easily accessed by our modellers, along with anyone else who might need access, e.g the client or other members of the design team. The two data sets can be viewed together and toggled between. And of course, being online, it is accessible from anywhere in the world with an internet connection. Our expert team will provide training on using the software.

Back in the office, we import the point cloud data into our BIM software (ARCHICAD) and thereafter it is simply a case of building the BIM model by “3D tracing” the points in the cloud. Sounds easy! In reality, it is a complex task that is only carried out by skilled and experienced operatives. In Lees Associates’ case, all of our modellers are architecturally qualified. And that is where our service really stands out from traditional surveyors: all of Lees Associates surveys are carried out by qualified Architects, Architectural Technologists and Architectural Assistants (who, despite their title, have post-graduate degrees in Architecture).

This process allows us to typically have a complete and reliable BIM model of an existing property within 2-3 weeks of the scanning visit. This remarkably quick turnaround, combined with the level of information that the model contains, is of huge value when it comes to progressing the design of the scheme, especially for heritage and other renovation projects. The design team will be working from accurate data from the outset and will not need to rely on assumptions that might prove to be wrong at a time in the future when the remedy might be a costly and time-consuming one. And if anyone wants to check any aspect of the model, they will have access to not only the original point cloud data but the photographic “model” too. 

And if all of this sounds expensive, you’d be wrong. If Lees Associates are appointed as Architect as well as Surveyor, the building of the model is free! This is because the time and work a good survey can save on a project makes it more than worth our while. So it’s win-win!

What are the benefits?

• Time on site

  Once the scanning is complete, we have all the data we will need. No return visits are necessary.

• Completeness of survey

  The scans capture everything visible, and are digitally stitched together to create a point cloud model of the whole building. If we need to check any dimension, no matter what of, the data is there to do so. This includes for neighbouring properties, which might have been incidental to the original scan but which might later prove important.

• Accuracy of survey

  Our stitched-together scans of say a 4-storey town house typically have a tolerance of 5mm: far more accurate than any traditional surveying techniques can produce.

• Photographic data

  The stitched-together panoramic photogrammetry that our scanner can also record allows anyone – client, Architect, surveyor – to explore every inch of the property, just like an indoor Google Streetview.

• Accessibility of data

  Both the point cloud data and photogrammetry are hosted securely so can be accessed by anyone, anywhere, at any time. Of course, access is strictly by invitation only.

• Accuracy of model

  The BIM model that we produce from the point cloud data is an accurate and complete digital representation of the property. This pays dividends later in the project when the proposed scheme is being implemented and coordinated in the model.

• Value

  If Lees Associates are retained as Architect for a project after having completed the survey, the cost of building the BIM model is free. This is because we know how much time and work a good survey can save on a project.

• Survey by an Architect

  All of our surveyors have graduate and post-graduate degrees in Architecture and have a comprehensive understanding of construction. Better still, if we are appointed as Architect for the project, the team who will deliver the project will do the survey and build the model, giving them an immediate and intimate knowledge of the property inside and out. 

• Efficiency of handover

  If Lees Associates are appointed as Architect as well as Surveyor, the need to transfer third party survey data into the Architect’s software and templates is eliminated. This is a process that can regularly take a number of weeks to iron out issues ranging from software incompatibility to using different layering and labelling standards and is plays a big part in our decision not to charge for the BIM model if we are appointed in both roles.