As part of our workflow, we routinely scan buildings and spaces, this lets us create an accurate and detailed model of the existing building.
A point cloud scanner sends out laser beams that then return to the scanner when they hit a surface, the resulting scan is made up of millions of points that map out the surfaces. You can see an example of a scan below.
At first glance, it can seem like the point cloud scanner is an expensive and time-consuming way to survey a building. The scanners themselves are pricey, even for an entry level scanner and with some scanners you may need a phone or tablet, as well as software to collate the scans. Scanning a large building, inside and outside, can take a whole day depending on the type of scanner you use. So why do we do it?
Traditionally, surveys were done with a tape measure or laser measure. This way of surveying can be done quite quickly but it is susceptible to human error and no matter how thorough you are, inevitably when you get back to the office, you’ll find another measurement that you need but didn’t take. With the point cloud scan, we have a complete scan of the building at hand whenever we need to take a measurement. The scanner we use also takes 360 photography so you can go back and do visual checks of the space. Ultimately, it means that we only need to go to site once, saving time, money and reducing carbon emissions with travel. The other benefit of the point cloud scan is how accurate it is. The scanner we use has a ranging accuracy of 4mm over 10m or 7mm over 20m!
With the latest iPhone and iPad models, the cameras now have lidar, meaning that you can scan using one of these devices and an app. We were keen to investigate this and see if this could be a quicker and more cost-effective way of scanning.
A member of the team scanned our VR suite using the point cloud scanner, using our normal methodology. We then carried out a scan using an iPad and a free mobile scanning app, following the instructions provided by the app – this involved holding the iPad and moving around the room as it scans. To get a more reliable comparison we also scanned using the same mobile scanning app but used a tripod. Spot measurements were also taken using a Disto laser measure, of the height, length, and width of the room.
Once all the scans were collated, we were able to compare them visually and by taking the same measurements in each scan. The results are shown below, the point cloud scanner and laser measure were within a few mm of each other, the mobile scanning app using a tripod was slightly out, but the freehand scan was significantly different to all other scans and measurements.
The mobile scanning app is undoubtably far quicker and cheaper, but our priority is to create accurate and detailed models, so for us the point cloud scanner is still the winner and worth the investment in time and money. Obviously, technology is constantly evolving and improving, and we will continue to test scanning apps to ensure that we are always offering our clients the most cost-effective solutions for surveying while not compromising on quality.
If you are interested in getting a scan of your building or have any questions, please get in touch with us!