tion, so it is mostly finished before you begin the next scan. While it is doing the next scan, only a few minutes each, the Perspective software is doing the cloud registrations. You can see if there were any problems with the scans or registrations; if not, there is a refinement step that performs a least squares adjustment of the registrations.” The scanning crew does not need to do much prep before scanning, except to cover up mirrors and close curtains and blinds to remove reflections, per the contract specifications. Furniture and fixtures in the flats were not a problem. LE34 sent a short video of each room to Ramboll along with the point clouds so they could identify and connect features partially obscured by objects in each room. The scanning and cloud merge for each flat is completed on-site in about 45 minutes, including the time to move to the next unit in the same housing block. “We did not need to use the scanner globe targets like those we use with conventional scanners, as the registration is automated,” said Møller. “But the contract called for us to use them. This was OK because we could use the globes as part of our QC process.” In the office, LE34 developed scripts to open Trimble RealWorks, check the registration quality, provide a report of the results, and export the data to Revit. They added a script to make use of the globes, detect them in the point clouds, and check the relative integrity. “The contract called for 2mm accuracy on the globes and 4mm on the points cloud registrations,” said Møller. “There were only a few times we did not meet this and then we would adjust the registration in RealWorks. Usually we were between 1mm and 2.5mm.” One Scanner LE34 has produced almost 60,000 scans, encompassing thousands of sites with their first X7. It is almost unheard of for legacy scanners to get this much use without having to be sent in for calibration. “We may have a scanner out of service for two or three weeks for calibration, and
this can be quite costly over the life of a scanner,” said Capion. “With the X7 we do not have to worry about this.” LE34 keeps long-range scanners, like the Trimble TX8, in their in- ventory for large-scale outdoor projects, using target globes and do- ing cloud registrations in the office in RealWorks. But their success with the X7 has prompted them to purchase four more, and they are beginning to test out the units on different types of projects. As Møller reiterates, “Being able to register and check the cloud in the field and eliminate much of the office work has great potential.”
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January 2021
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