Since 2012, Southern Survey and Design has embraced terrestrial LiDAR data collection. Being several years ahead of the market acceptance for this new technology, our experience was hard won and now valued to our clients. There is no comparison in the level of detail, precision, and completeness that LiDAR data provides in complex environments. We measure objects. As service providers, we go to where those objects are every month to laser scan in the field.
Equipment
We use a Trimble TX5, phase based scanner that is essentially a Faro Focus. For registration, Koppa spherical targets have been proven excellent as we use four 250mm spheres and ten 150mm spheres on site. In addition, we use checkerboard targets and can perform cloud to cloud registration. On every site, there is always a survey control aspect as we place our scanned point cloud on the client’s specified coordinate system. Whether the point cloud coordinates are in plant grid or geodetic, our proprietary workflows assure end user utility.
Scan Settings
Being self-taught and having made so many mistakes implementing this technology, we collect scan positions to optimize resolution and point coverage. You can’t scan what you can’t see! This has forced our field crews to utilize man lifts, custom jigs, and unique placements of the scanner. Although we can colorize the point cloud, it increases the time per scan station and colorized point clouds are sometimes difficult to model. We have learned to decrease the resolution and increase the setups to provide the best four-way coverage of objects in the field.
File Types and Software
The native format of our scanner is .fls and augmented reality software is provided by Faro Scene LT at no cost to our clients. Some of our clients utilize other file formats like .las or Autodesk software suites like ReCap. Our office converts file types and uses FTP sites to deliver large datasets. The point cloud is used as construction points during the modeling phase. Whether you use Plant 3D, Cadworx, Navis, or other smart drafting programs, the point cloud can be indexed and xref into your workflow.
Modeling
Using clipping boxes, modeling is done by layer. You can remove all points above the terrain, down-sample, and create a digital terrain model. Next, focus on modeling all of the concrete footings and extruding the substrate to plan specs. Structural steel can be modeled with the specifications of equipment catalogs loaded into your drafting software. As layers are modeled, the cloud is cleaned up. Next focus on nozzles, flanges, elbows, and tees. Pipe runs can be modeled and valves can inserted, scaled, and rotated. Finally, stock models like skids, towers, compressors, tanks, and facility equipment is added. The use of intelligent modeling software will allow the drafter to create isos, P&ID, nozzle reports, and plan sets.
Time Frame
What takes us a day to scan will only take a few hours in the office to register into a point cloud. The modeling process could take several hundred hours though. Although several intuitive modeling softwares exist, there is no quick solution. Often the modeling aspect is offshored to large drafting firms in India and the beginning product for our clients is the smart model drawing.
Southern Survey and Design has facilitated these scan projects at every stage. If you could benefit from this service, please contact us. We write bid proposals for terrestrial LiDAR weekly and our project portfolio is extensive.
