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Reality Capture:

Laser scanning, drones bridge gap from surveying to Building Information Modeling

Pete Kelsey of Autodesk, Inc., flies a DJI Phantom II drone outside the cadet chapel in June 2014.

Base Surveying to Reality Capture: Technology progression.

Cadet chapel laser scan in Autodesk InfraWorks.
Lt. Col. Patrick C. Suermann, PhD, PE, LEED AP
U.S. Air Force Academy assistant professor

Roger Clarke
21st Space Wing GeoBase program manager and engineering support chief

    Today's Airmen are much more advanced and able to process visually rich, 3-D information more readily than their instructors and commanders were at their age.  Think of a corollary: video games.  "Us old guys" remember playing the original Atari or Nintendo in our friends' basements in the 80s.  As Mario and Luigi ran along the x axis they occasionally jumped in the positive y direction or fell down a tube in the negative y direction to try to collect a few coins.  Today's graduating high school seniors are used to playing first person shooter games with photo-realistic, real-time rendering graphics, while competing against networked friends around the world.  Times have changed!

    Therefore, it should make sense that our requirement for facility data will also keep up with our need for increasing amounts of reliable, real-time data.  It's hard to believe now, but when GeoBase was first rolling out in the early part of this century, people often wondered aloud, "do we really need high resolution aerial imagery of our own bases?"  Perhaps people were stuck in a paradigm where they thought of U2 aircraft collecting photography on covert movements in far-away countries.  Thankfully, we shifted our paradigm and "one base, one map" helped advance the way we thought about our common installation pictures and associated data.

    Similarly, teaching surveying has also evolved.  While the school house at Fort Leonardwood, Missouri, and the U.S. Air Force Academy in Colorado Springs, Colorado, may still teach the traditional surveying principles through classic geometry and theodolite data collection, they've moved forward by also including total station and global positioning system data collection.  Now, there are new technologies helping to better document base as-built conditions:  reality capture through laser scanning and remotely piloted aircraft.

    For being "new," these technologies aren't even all that new!  In 2011, Roger Clarke and his team at the 21st CES had a challenge of supporting the largest, most geographically disparate wing in the Air Force.  Their squadron is responsible for geographically separated units at places like Thule Air Base in Greenland to others at Maui, Hawaii.  They solved the problem by using a Leica C10 ground-based High-Definition Survey ScanStation.  This equipment comprehensively captures vector and image data quickly.  Using light detection and ranging, the scanner hits all the points it sees with a laser and times how long it takes for the points to come back.  After a 360-degree sweep, it completes another revolution to capture the "picture" - populating all laser-acquired data points with the colors and images it sees in the photo capture.  The result is something out of the first-person shooter video games our junior enlisted are likely playing in their dorms:  hyper-accurate photo-realistic, virtual environments.  It's taking 3E5s from simply "surveying" where they collect a few data points to "reality capture" where they get everything that can be seen at once.

    In the summer of 2014, the 21st CES and the CE Department at the Air Force Academy partnered with Autodesk Corporation to conduct a reality capture at one of the most iconic facilities in the Air Force, the cadet chapel.  In one week, government civilians, officers, enlisted, cadets and contractors collected gigabytes of data about this 50-year-old historic landmark.  Two types of laser scanners were used:  the Leica C10 mentioned earlier, and a FARO Focus3D X330 scanner.  Additionally, a DJI Phantom II drone was piloted by Autodesk under the thorough supervision of a  USAFA RPA pilot and small UAS Test Manager, Maj. "Pokey" Gorrell of the USAFA's Astronautics Department.  There are now videos and still shots from the GoPro camera on the drone that can be used to survey every bit of the outside of the chapel from the crumbling foundation to the laser scanning at the apex of the spires.  From the laser scan, the end result was equally spectacular.  For the first time ever, you can see all sections of the chapel in real time by sectioning the laser scan point cloud.

    More important are the downstream uses of the data.  The principle of building information modeling, or BIM, according to the National BIM Standard is to digitally represent the physical and functional characteristics of a facility from inception onward.  As such, the BIM should serve as a shared resource for collaboration where information can be authored once and used again and again.  In this case, modelers are using existing information and all the newly collected information for adding the model to macro level views in InfraWorks and smaller scale facility analysis for energy modeling and simulations.  Eventually, this will all be used for a likely renovation in the coming years which will require completely disassembling the structural envelope and reassembling it with improved flashing and waterproofing.  These models will be invaluable to the planning of that effort.

Editor's Note: Suermann helped launch GeoBase at Andersen AFB, Guam, in 2000 and BIM military construction requirements in fiscal 2010.  Since 2012, he's served as a professor in the U.S. Air Force Academy Department of Civil and Environmental Engineering. Clarke served as an EA from 1980-2000 before retiring and joining the civil service.  He's led innovative 3E5s at Nellis AFB, Nevada, and Peterson AFB, Colorado, since that time.  Additionally, he teaches courses in GIS for various higher education degree-granting institutions.