GeoWorld August 2012

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"This is where [the technology] comes in handy—the capability of really tight tolerance checks and the speed of being able to get it done quickly," he says. Clay used a total of seven targets for his control; it's recommended that at least four targets be scanned. After the targets were scanned, Clay set the scan area by turning the turret head to arbitrary points at the top left and bottom right of the desired area, and input the desired point density. These points were slightly out- side the control targets, so previous and future scans of nearby areas could be blended together. Putting Data to Work After Clay finished a scanning sequence, raw point-cloud data were copied from the data card in the GLS-1500 and sent to Adam Arrington, vice president at Earl Dudley. Arrington received the point-cloud data and scanned images as well as a file containing control-point data, and he imported them into Topcon ScanMaster soft- ware. He registered the data together in ScanMaster, essentially performing quality assurance/quality con- trol, and stripped the file down into Schuff's steelwork and surrounding structures that Fugera needed to view to ensure correct relative positioning. Taking a PCG file provided by Arrington, Fugera imported the point-cloud and dimensional data into AutoCAD using kubit software, which allows Fugera to compare the point-cloud coordinates with the AutoCAD building model based on the official survey. ScanMaster Viewer allows him to view images of Schuff's steelwork from where the scanner was located. Along with the ScanMaster and AutoCAD files, Fugera viewed Schuff's steelwork against the entire building structure on a Tekla Structures file developed by Schuff's drafting department. The east side of the Music City Center features eight radius variations and five pitch variations at the roof. "I primarily use ScanMaster to make sure that I've got everything I need, and, if I don't, then I direct [Clay] to do another scan in a different area to catch what he's missed," says Fugera. "But as far as inserting the scan into the model with the control points, Adam does that for me, which is a great asset." The modeling process was allowing Schuff to make immediate incremental corrections to its steelwork when necessary. Fugera, who years earlier used a total station to as-built survey the distinctive "turkey tail" domes on the roof of the Orange County Convention Center in Orlando, Fla., wishes scanning technology had been available back then. "Using the point cloud actually locates [the steel- work] exactly where it is, compared to where it should be, using base control that we establish throughout the building and through the 3-D model, showing where it's been designed to be," notes Fugera. "The scan and the point cloud give me an exact picture of where everything is." Point clouds collected by the Topcon GLS-1500 show sections of the steelwork at the Music City Center. Don Talend is a print and e-content developer for Write Results Inc.; e-mail: AUGUST 2O12 / WWW . GEOPLA CE . COM 29 SCHUFF STEEL DON TALEND

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