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Published: 08/24/2016
Color is a big differentiator in the world of 3D scanning, but when it comes to inspection or reverse engineering, it’s usually not mandatory and sometimes not even important. However, color is paramount in applications such as heritage preservation, which is the 3D scanning and digitization of artifacts for preservation, analysis, and virtual museums.
During the fall of 2014, King Tutankhamun was to be part of the Crossroads of Civilization exhibit at the Milwaukee Public Museum. One of the most famous Egyptian pharaohs, Tut reigned during the mid-1300s BC, from the time he was about 9 years old until his late teens. To perform color 3D scanning of objects related to King Tut, Creaform provided the 3D measurement technology and engineering services.
A life-size replica of King Tut riding his chariot drawn by two horses was one of the exhibit’s main attractions. Visitors can’t get closer than 6 m to the actual replica, so a real-size scan was performed. The museum wanted to provide a virtual tool to the visitors, available through an electronic tablet. For this project both the Go!SCAN 20 and the Go!SCAN 50 3D scanners were used. The application, which understandably needed to reproduce all the colors faithfully, provided a closer look at the clothing, jewelry, and gear used during King Tut’s era. Certain objects were individually selected and manipulated to further analyze and understand the manufacturing of the chariot's components.
A Creaform application engineer digitized nearly 30 items, in partnership with Vince Anewenter and Jordan Weston from the Rapid Prototyping Center at the Milwaukee School of Engineering. As experts in 3D scanning and additive manufacturing, Anewenter and Weston spent three days at the museum scanning portions of the exhibit. Weston was a first-time user of the Go!SCAN 50, and he found it easy to use.
To scan larger objects such as horses, the replica of the king, and the chariot, we used the Go!SCAN 50. It has a larger light pattern and provides very fast scans. We had to scan the horses multiple times with different layers of clothing (e.g., leather straps, hats, coverings), and we wanted everything to fit the horses correctly. It was possible to pre-align the scans with a prior-saved target model for perfect alignment, which was a major advantage.
The Go!SCAN 20 model was used to scan objects with smaller details and also scan thin objects on both sides. The scanner’s Matching Point function allowed us to merge two sides of thin objects with common targets, which would have been practically impossible to do otherwise. The results were quite amazing!
Our scan of a 3,000-year-old carved tablet actually made it possible to see more details than with the naked eye. The museum directors were impressed and even hinted that these details could reveal the social caste of the man depicted on the tablet, based on some newly revealed hieroglyphics found on his forearm.
To perform this specific scan, the Natural Features function was used, detecting color elements as part of the scanner’s tracking in space. Using the Go!SCAN 20 and the color camera, 3D scanning was done without any problem, and no targets had to be affixed on the precious artifact.
Working with the scan data, the first step was to align the scan on the center of the object. We used VXmodel, a post-treatment software that enables users to smooth rough surfaces and fill holes to make it watertight for better quality. By filling holes with VXmodel, it’s also possible to apply texture information where the surface was originally missing.
Files were then transferred into a multimedia software. Then, triangles were converted into squares to optimize the performance of the 3D model in video game engines. The models were then finalized: Color was applied where it was lacking, such as in undercuts and hard-to-observe areas. Finally, all of the objects were globally aligned by projecting the 2D image onto the 3D model.
Increasingly, the virtual museum will draw young visitors, and may even become the new standard to knowing the secrets of our past. Creaform will be proud to be part of the process.
Links:
[1] http://www.goscan3d.com/en/applications/heritage-preservation
[2] http://www.mpm.edu/plan-visit/calendar/crossroads-civilization
[3] http://www.creaform3d.com/en/technical-specifications-goscan-3d
[4] http://www.msoe.edu/