KOREC Opinion: Melvin Penwill, 3D Laser Scanning Specialist

Verification, along with documentation for sub-contractors and as-built surveys are areas where 3D Laser Scanning can really add value to a construction workflow.

Scanners are so much easier to use than a total station so why’s the take up so low on construction sites? I thought I’d share a few thoughts!

Construction needs laser scanning now more than ever. Why do I believe this? Because when I go on to construction sites, yes, I do see total stations but I’m also still seeing tape measures, spirit levels and notebooks! The old ways can be functional and achieve a ‘result’ but to manually check every aspect of a large-scale project is extremely time consuming (unsustainable during a skills shortage) and prone to inconsistencies (we’re all human). In short, a few millimetres out on a ground floor can lead to 50mm out elsewhere.  Clashes and rework inevitably result in additional expense and delays costing the industry £2 Billion in the UK each year with 49% of UK construction leaders reporting frequency of errors and rework as occurring a couple of times a week and 48% a couple of times a month*.  

3D Laser Scanning has taken off within other industries including surveying, forensics, civil engineering, rail, steel fabrication, facilities management etc. When I talk to professionals in these areas it’s very much about the benefits and gains. When I’m in the construction environment, it’s very much about overcoming objections.I don’t believe that this is down to the traditional opinion that ‘construction is slow to adopt new technology’ and industry surveys back this up – for example, over 98% of polled construction companies in the US & UK use some form of AR on their projects and 87% use BIM*.  Instead, the construction industry is raising valid concerns that must be addressed if this next step towards a digital site is to be taken.

Here are the five points I hear most: 

I’ve got a total station that does the job just fine 

Just as the total station superseded the dumpy level, it’s now time to take another step forward, and that step should be a 3D Laser Scanner. First up, you can trust the accuracy of a laser scanner – and we get asked this a lot. For example, all of the Trimble X Series scanners offer a 3” arc over 20mm, that’s 1mm accuracy. They also self-calibrate at the beginning of every job so you can have total confidence in the accuracy of your collected data.  

Therefore, it’s delivering sufficient accuracy for construction applications. However, that’s not where the real value lies. A total station can only ever tell the story of the exact points collected which of course may be completely correct and as per the design. Laser scanning tells the whole story – including everything that’s happening between the total station points – and that’s where the ROI lies, this is vital information for avoiding rework costs and delays. The picture delivered by ten carefully surveyed total station points simple can’t compare to the level of information provided by the thousands of points collected by a laser scanner.  

Using a laser scanner on site is relatively easy but it might take me a week to extract the information I need. 

You can use your collected point cloud immediately thanks to on-site registration for error checking (a standard feature with Trimble’s X7, X9 and X12 Laser Scanners). Of course, you can check again back in the office but all the answers you need for reacting immediately to an error or clash on site can be viewed through functionality in the included on-board software, Trimble FieldLink, including setting-out errors, clashes, verticality issues and floor flatness.  

To get value out of a point cloud, I’d need to invest in hardware and software that can handle massive data sets. 

Again, this might have been the situation in the past but now you can carry out essential functionality in the field using the FieldLink software. Back at the office, Cintoo Cloud is a great asset, allowing you to store massive 3D point cloud datasets in the cloud, eliminating the need for extensive local storage and enabling easy access from anywhere. I’ve got a customer in demolition who scans buildings for recycling purposes and lets colleagues view this data in Cintoo which has massively helped his business at a price on average of £1,200 per year for 500 scans. It’s really easy to use and extract data from, perfect for sharing clash information.  

We’d have to learn about another new technology 

The good news is that a 3D Laser Scanner is far easier to set up and operate than a traditional total station which is why take-up has been so successful in industries that are not traditionally related to survey. We’ve had people scanning statues for documentation, bar & restaurant interiors for planning and all sorts of buildings by architects. We are currently facing a significant skills shortage in the construction industry and this type of technology can attract a forward-thinking generation that has grown up with smartphones, however, it needs a forward thinking buyer to start the ball rolling.  

There are so many different types of laser scanner, it’s hard to know where to start 

Correct, the market offers many types of laser scanner which is why I’ve also checked with my KOREC construction colleague, Sam Hough for a recommendation on the best 3D Laser Scanning system for construction documentation and as-builts. Here’s his list: 

Trimble X7 or X9 3D Laser Scanner (must haves include on-site registration, auto-levelling, auto-calibration, ease of use, IP55 rating and a handle!) 

Trimble FieldLink Intuitive software with some great functionality running on a T10x rugged tablet 

Cintoo Cloud for viewing and sharing of large point clouds and further functionality for measuring etc eliminating the need for further software/hardware outlay.  

…. which led to an interesting chat with Sam following our recent membership to GIRI – Get it Right Initiative. Sam agrees that 3D Laser Scanning provides a highly effective solution for as-builts, documentation and error/clash detection but he’s ready to argue that it would be far more pro-active to avoid errors and solve any potential problems in the first place!  And this is why he will be my next KOREC colleague to share his opinion on LinkedIn…coming soon. 

Do you agree with my conclusion that construction is ready to take on 3D Laser Scanning? Please do comment. 

For further information on any of the above, please contact myself, Melvin.Penwill@korecgroup.com, or sam.hough@korecgroup.com visit here for full contact information. 

*XYZ report Constructing Tomorrow