The good news was that Danish surveying consultancy LE34 won a bid to scan thousands of housing flats. The bad news: Traditional scanning workflows would involve too much time per flat. In order to succeed, LE34 needed to radically reduce the time and cost both on-site and in the office. The solution involved creating workflows to leverage a self- calibrating scanning system with automated cloud registration that cut field acquisition time and nearly eliminated manual office processing. Thousands of scans later—and counting—their new system and the process it has enabled, continues to exceed expectations. Thousands of Flats Boligforeningen AAB is a non-profit that administers nearly 20,000 homes and flats in the Greater Copenhagen area, managing and leas- ing these to achieve sustainability and affordable-housing goals. AAB issued an EU tender to scan thousands of these units to streamline the process of tenant changes. By using 3D models of units, AAB could reduce estimating costs for unit refurbishment prior to new tenancy to a single site meeting. LE34, a prominent multidisciplinary Danish surveying consultancy, sought to bid on the project but Engineering Surveying Director An- ders Nygaard Møller and his colleague, Chartered Surveyor Richard Lindquist Capion, realized that conventional scanning workflows might not provide the competitive edge needed to satisfy the tender. AAB, required 3D models in Revit for each type of flat, along with the offices, shops, basements and stairwells in each housing block. To turn the point clouds that LE34 created from the scans into the finished 3D models, LE34 tapped the expertise of Ramboll, a leading global engineering, architecture, and consultancy company. Capion said “With a 3D model, AAB can estimate the quantities of painting, carpet, piping, etc., that need to be replaced or repaired before the next tenant moves in. The property manager, tenant, and contractors can all view and measure in the 3D model. With one site visit, AAB and the departing tenant can calculate quantities, send these to the contractors and determine how much of their deposit they get back. Our job is to scan the flats, merge the point clouds, perform QA & QC per the cli- ent’s specifications, and export the clouds for each flat into Autodesk ReCap for Ramboll to create the Revit models.” LE34 was looking to automate the processes. Møller and Capion were intrigued by a recent demonstration of a new 3D laser scanner, the Trimble X7, and worked with Trimble distributor GeoteamA/S to acquire their first X7 and get up to speed on operations. “It was fast enough – 500,000 points per second,” said Møller. “But what really stood out was the automated cloud-to-cloud registration Scanning for Property Management How a Danish surveying consultancy uses advanced scanning technology to support affordable housing. By John Stenmark
in the field and on the tablet. The on-site results looked to be as good as what we could do registering the point clouds in the office. This eliminates much of the office time for processing the scans, essentially cutting our time for each site in half.” Scanning Flats Becomes Flat Simple The LE34 team notes several features that have enabled them to scan up to 10 flats per day. Unlike other scanners they have used, notes Møller, the X7’s base is the same kind of compensator unit used on high-end total stations. “It does a self-calibration in a few seconds. So it is level, we don’t have to worry about that, no errors in that,” he said. “It comes with a light carbon fiber tripod, and we can just pick up the whole thing and move it between scan stations.” Henrik Kjærsgaard Christensen, a LE34 Chartered Surveyor who over- saw much of the scanning, was impressed by the system’s simplicity. “You do 15-20 quick scans of each flat, shop, or office and the scans register automatically. It is easy to train someone to operate and look for any issues. We can do this in the field without having to do the registration in the office later. If needed, we could even hire surveying students to do the scanning,” said Christensen. Capion explains the in-field QC process. “You register scans as you import each from the scanner into the tablet; this is via a WiFi connec-
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csengineermag.com
January 2021
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