A GrandSLAM for building scans – Spatial Source

The Leica Geosystems BLK2GO handheld imaging laser scanner weighs only 775 grams, including the internal rechargeable battery.

C.R. Kennedy’s team in Western Australia recently did a site walk on a client site in conjunction with local surveying firm Links Surveying, which needed to capture an existing semi-occupied office complex and produce leased floor plans.

It was decided that the Leica Geosystems BLK2GO handheld imaging laser scanner was the ideal product for the task, as it would be the best and most time-saving solution for the task.

The BLK2GO recreates spaces in 3D by capturing images and dimensionally accurate 3D point clouds in real time and uses Simultaneous Localization and Mapping (SLAM) technology to capture the user’s trajectory through space. The LIDAR data is automatically combined with the images to produce a colored point cloud.

The device can scan over and under objects, through rooms and doorways, around corners and up and down stairwells. Thanks to the SLAM spatial awareness technology, the BLK2GO always knows where it is and where it has been.

According to Leica Geosystems, the BLK2GO is the smallest two-axis LiDAR available with what is claimed to be best-in-class accuracy. The device is enclosed in a fully protected and encapsulated dome that scans at up to 420,000 points per second. Both axes rotate continuously while scanning.

No tripod is needed and the data is collected on board. The vision system is a 12-megapixel camera for high-contrast images plus three panoramic cameras for visual navigation via SLAM, point cloud coloring and capturing panoramic images. The handle houses the WLAN connectivity electronics, a rechargeable battery capable of 45 minutes of continuous scanning, data storage for six hours of scans and a USB-C port for high-speed data transfers and edge computing. A light guide surrounding the BLK2GO provides user guidance during scanning and communicates device status and data quality. All in all, the device weighs only 775 grams.

The BLK2GO’s GrandSLAM technology combines the high-speed, two-axis LiDAR, multi-camera vision system and an inertial measurement unit to make the unit self-navigating.

Walk and scan

For such a job, a surveying company would traditionally use a Leica Disto to measure the overall dimensions of the room before processing those measurements later through the chosen CAD software. Doing it that way with a Disto or total station could have taken two to three days to work through the building and just capture the room dimensions one at a time… let alone the further work that would have to be done to interpret the data manually in the CAD software.

With the BLK2GO, that kind of workflow is a thing of the past.

The CR Kennedy team met Links Surveying on site and discussed the best way to go about the job before scanning began. Once ready to go, the team spent a total of just three hours at the site with a total of 106.97 minutes of scanning time over 30 different walks.

Each lease was split into several scans, depending on layout, with walks through the common area of ​​the building to allow the Leica Cyclone Register360 software to link the scans together with sufficient overlap. Some of these walks even took place through active leases with a plethora of moving people – this caused no problems and didn’t affect the finished point cloud or increase the scan time.

Top view of the point cloud data on the ground floor of the scanned building, via Register360.

The next step was to process the data back at the office via Register360. This involved importing 70GB of data, reviewing the individual scans, cleaning up any annoying point cloud noise, and linking the 30 different walks across the two floors and exterior of the building. This took about four hours, most of which was spent on the import phase.

Once the team was happy with the data and completed the QA checks on the scan bundle, it was time to export the data to a .lgs file for linking with CAD software via Leica CloudWorx. In this case, the team decided to model the floor plans using Revit from Autodesk and Leica CloudWorx for Revit. It took less than two days to model the site (windows, floors, doors and walls) using the point cloud data and to produce floor plans and room diagrams for leased areas.

It’s no exaggeration to say that, thanks to the capabilities of the BLK2GO, a finished product can be generated in three days for a job like this.

Scanning a building with the BLK2GO

Time on location: 3 hours (2 hours of scanning)

Site type: Two floors of semi-occupied office space

Location area: 5.026m²

Raw data size: 30 walks totaling 70 GB

Processed data size: 5.17 GB .lgs file / 608 MB .rcp file

Processing time: 4 hours (with Register360)

Modeling Time: 2 days (with Revit and CloudWorx)

Information provided by CR Kennedy and Company.

#GrandSLAM #building #scans #Spatial #Source

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