Necessity Drives Innovation: Developing New 3D Capabilities on Demand
Written by Michael Raphael
posted Friday, 04 March 2011 - source lidarnews.com
Today’s applications and uses for 3D laser scanning are clearly quite broad – from such diverse worlds as facilities to forensics to shipbuilding. One of the successful early adopting worlds is also historic preservation. Accurate three-dimensional scans of complex historic sites, structures, and objects, provide conservators with a powerful tool for analysis – 3D digital models. Often this data forms the basis in a digital format for a virtual reconstruction of the site or object, allowing further analysis and certainly a compelling visualization.
From our beginning in 1995, our team at Direct Dimensions, Inc. has pushed the use of our many 3D scanning and modeling tools into this world of historic preservation. One of our earliest opportunities came in 1997 during an industrial project with the U.S. Navy. While using the then new FARO Arm portable CMM to reverse engineer small-scale ship test models, a Navy historical conservator approached and asked if we could use this amazing tool to capture a particular 100-year old bronze bust of the former U.S. Navy Admiral Melville.
Since the FARO Arm at that time only digitized discrete points via probe contact, this request unknowingly formed the basis for our integration of a laser line scanner onto the FARO Arm and the development of software tools by Innovmetric in PolyWorks to handle this new form of dense scan data. Including that technology development time, the overall project back in 1997 took over three months to complete resulting eventually in a ‘watertight’ 3D polygon model in STL format.
Today, by the way, with our current and broad set of various scanners and softwares, we could complete this same project in less than three hours!
This technology evolution reminds me of how my firm began using terrestrial 3D laser scanners for historic preservation. A few weeks after the tragedy on September 11, 2001, the U.S Government approached us with a very special request. Various agencies and organizations became interested in documenting significant American cultural landmarks, monuments, sculptures, and buildings in case of similar catastrophic events. The group asked Direct Dimensions to demonstrate its developing capabilities for 3D laser scanning and digital modeling and they offered the famous Lincoln Memorial in Washington D.C. for this effort.
We mobilized our scanning team for the one day on-site demonstration on a rainy chilly day in late December 2001 for a broad audience that included officials from the National Park Service, the Smithsonian Institute, the GSA, the Architect of the Capitol, and the Historic American Buildings Survey (HABS/HAER).
Using a then relatively new Cyra 2500 scanner mounted on its traditional tripod, we gathered millions of 3D data points from nearly 20 scan positions focused on the front entrance area of the Lincoln Memorial, the main interior chamber, and of course Abe Lincoln sitting in his chair. While the scanner clearly impressed the high-ranking audience, we knew its true value would be apparent with the delivery of the accurate 3D digital models.
During the next several weeks back at the Direct Dimensions facility only an hour from Washington, the team processed the raw scan data into watertight 3D mesh models using Innovmetric’s PolyWorks software, same as we did for Admiral Melville. The resulting digital models ultimately included the front steps of the Lincoln Memorial, several of the front columns and above entablature, elements from the main interior chamber including his famous speech carved behind him, and of course much of Abe Lincoln seated in his marble chair.
To further demonstrate the range of possibilities for having this historical data in a 3D digital format, we collaborated with our partners at the U.S. Army’s Advanced Digital Manufacturing group at Aberdeen Proving Ground to create a 24-inch scaled physical reproduction using rapid prototyping, or 3D printing. Back in 2001 this was considered a very unusual 3D print and clearly demonstrates the end-to-end capabilities for laser scanning.
A copy of our finished digital models now resides in the archives of the National Park Service. Should any repairs or restoration of the Lincoln Memorial be necessary, the Park Service now has an incredibly accurate 3D model, down to the millimeter, to aid planning and restoration effort.
Clearly the 9/11 tragedy opened our eyes to the idea of capturing historic cultural memorials, artifacts, and buildings. Since then the world has endured many more tragedies, man-made as well as natural, and there is no question that more will happen. We will lose precious bits of our history and culture – this is inevitable. So why not digitize them now? Clearly we have the technologies, the capabilities, and the reasons. We should, because we can.
Read the original posting on LiDAR News.com