Modeling Easter Island’s Moai in 3D using Geomagic software

Digital archives create a critical 3D reference to track erosion and damage to this World Heritage Site

In 2008, a tourist on Easter Island was charged with damaging a Moai statue – tearing off an ear lobe from one of the towering and scowling volcanic rock statues – an offence that can result in 7 years in prison and some hefty fines. Damage to the historic site is only occasionally caused by humans, but risks of damage from tsunamis and earthquakes is much higher, enough so that in 2007 a team from HafenCity University Hamburg began a 5 year project to digitally catalog the statues. The resulting 3D data would allow the experts to assess damage from all these known threats but also needed to be accurate enough to analyze damage by erosion.

It is illegal at any time to touch these ancient statues erected between 1300-1600 AD, so the Commission of Extra-European Culture of the German Archaeological Institute teamed with experts at HafenCity University Hamburg, bringing in the University’s expertise in non-contact laser scanning to handle the project without breaking any laws.

Scanning the Moai of Easter Island using Geomagic software and a ZF scannerThe team, which included Dr. Burkhard Vogt, Professor Thomas P. Kersten, Dipl.-Ing. Klaus Mechelke, and Dipl.-Ing. Maren Lindstaedt , conducted 2 4-week missions in February and March of each year between 2007 - 2011 in cooperation with Chile’s Consejo de Monumentos Nacionales, Santiago, and CONAF (Corporación Nacional Forestal). They scanned 11 sites, and a total of 46 moai, processing the raw scan data through 3D Systems’ Geomagic Studio software to create highly accurate 3D models.

Each passing year, the same sites were rescanned using carefully placed targets and markers to ensure that the same scanning positions were used. The resulting data were processed and then compared in Geomagic Studio to highlight even the most minute changes that may have resulted to the statues.

 

While the experts are anticipating that erosion or weather conditions could only make changes by millimeters across a ten-year period, this can only be compared if both reference and comparison data use the same fixed coordinate system.

The real statue and the 3D scanned image

“While much of the damage done to the moai has been through natural disasters, tales of tsunamis and human damage illustrate that it is absolutely essential to scan the moai for documentation and to have 3D digital copies of the moai on hand,” commented Professor Kersten at HafenCity University Hamburg. “While scanning will continue in the next years, the scanning and documentation of all registered 887 moai could take quite a long time. However, image-based recording systems in combination with dense image matching algorithms offer the best low-cost, flexible and efficient solution for rapid 3D documentation of these statues.”

 

Read more about the Geomagic scanning and reverse engineering software solutions at: http://www.geomagic.com/en/products-landing-pages/scanning