Scansite Creates Duplicate of a Famous Chilean Mummy
Reverse engineering helps in the recreation of a famous Chilean Mummy.
In 484 AD, the Western Roman Empire had just come to an end, while across the ocean on the South American continent, a young Chilean miner climbed down into a copper vein in the Atacama Desert of Chile. This young man, wearing braided hair, anklets of fur and a fabric loincloth did not return to the surface until being unearthed by a much later mining expedition in 1899. This mummy, entitled ‘Copperman’, turned out to be one of the most important discoveries ever made. The Atacama desert region is one of the hottest and driest places on earth. This fact, coupled with the inherent high mineral content found in the region, had resulted in a remarkedly life-like preservation of the body.
DUPLICATING A MUMMY
When the American Museum of Natural
History approached Scansite (Woodacre,
CA) to build them an exact duplicate
of the mummy, it was expected that
there would be many challenges in
reverse engineering something as unique
as ‘Copperman.’ One issue was the fact
that the mummy had a particular greenish
hue due to the high copper oxide content,
and it was actually imbedded with
hundreds of small reflective rock material.
Another was the hair on his head and the
fur ornaments he still wore. Scanners can
have a difficult time capturing data from
reflective objects, so the light from the
rock material could potentially compete
with the light being projected by the camera.
There was also the possibility that
the mummy’s hair might cause the scanner
light to fracture instead of bouncing
back cleanly for the CCD grid to read. In
both cases, the potential for scanner
noise, or unusable data, was fairly large.
Since Scansite knew they were going to make the highest resolution RP model possible, they also needed to get as much digital information as they could. They chose an ATOS III (GOM, Braunschweig, Germany) white light digitizing system that allowed them to capture 4,000,000 points per second, assuring them of having enough points to maintain a very high level of detail on something so large.
After gathering the data of the mummy, the files were taken back to Scansite’s studio for further editing. Because Copperman was permanently affixed to his display case, it created ‘line of sight’ issues, blocking the scanner from seeing the complete mummy. Data had to be created to fill in the entire back and underside of the mummy in order to have a ‘watertight’ file for the downstream operation.
BUILDING A MODEL
Once the data was complete, Scansite’s
job turned to producing a full scale rapid
prototype model. After researching the
various RP methods, the Z Corp
(Burlington, MA) process was selected.
Using the Z Corp process offered a high
performance composite build material
that was still economical for such a large
project. The data was shelled, and then
sliced into four printable sections, each
one with a 5/8" wall thickness, interlocking
seam lines, and internal support structures
of 1/2" beams to give the model
strength. Using the large format printer
(20" X 24" X 16"), meant building the
prototype in as few parts as possible.
Two hundred and twenty four hours and
5,451 square inches later, Copperman,
the prototype was created. Once the four
sections were printed, the legs and lower
torso were joined with epoxy and the
three sections were then packed in a specially
designed wooden crate for the
long trip to Santiago, Chile, where
Copperman, the prototype, is permanently
on display at the National Museum of
Pre-Columbian Art.
