Modeling Ancient Artifacts
Modeling in 3D can help preserve even the smallest artifacts, like beads and tiny bones. These fragile physical objects are essential links to the past, but they are often sequestered in museums or university collections to ensure their preservation. Creating virtual copies of these artifacts makes them more available for study. Researchers far from the collection itself can even receive a copy of the artifact by email.
Modeling programs such as Rhinoceros, from developers Robert McNeel and Associates, let researchers rotate a model, slice it at any angle to view a cross section, and obtain precise measurements of surface area, volume, and other features that may be difficult to measure manually. Scientists can also label or highlight important features and attach notes to virtual models. Combining that modeling ability with 3D printing can create accurate, detailed physical copies of artifacts. The 3D printer's software slices the virtual model into flat cross sections, and then the printer deposits layers of a material, such as plaster powder, to form a 3D object.
Archaeologists at Harvard University used digital modeling to reconstruct a shattered first-century B.C.E. ceramic lion, then printed an intact, full-color 3D replica of the sculpture. At Texas A&M Universty's Wilder 3-D Imaging Laboratory, researchers have printed ancient Roman anchors and a partial replica of a human skull.
Pennsylvania zooarchaeologist Jill A. Weber says that 3D replicas have enabled her study of equid remains from the third-millennium B.C.E. Syrian city of Umm el-Marra. Cultural heritage laws prevented the removal of the bones from Syria, so Weber created digital models using a laser scanner by NextEngine. She later printed replicas of 14 of the bones using a Z Corporation Spectrum Z510 3D printer.
The models, accurate to 0.13 mm in all directions, may now be the only trace of a previously unknown ancient hybrid of the donkey and the Asian wild ass. Amid Syria's violent political upheaval, the bones, along with other artifacts, may be lost or destroyed. "Now, the only access we have to that is from my scans and printed counterparts," she told Popular Mechanics. "If I hadn't done what I did, that information may well have been lost forever."
Since many sites crucial to humanity's past are located in politically unstable areas such as Iraq and Syria, Weber believes that 3D printing could help ensure that the archaeological record is preserved even in the face of danger to the artifacts themselves. These replicas are also useful tools for teaching or display, giving students and the public hands-on encounters with the past. Such encounters may inspire the next generation to develop the research tools of the future.
Mapping Ancient Sites
A surveying tool called a total station helps archaeologists record entire sites in precise detail by using optical beams to measure the distance between the instrument and another point, such as an artifact or the edge of a structure. Multiple instruments triangulate the location of each point on a 3D grid. When archaeologists enter all those coordinates into a geographic-information-systems (GIS) software program, they generate a 3D model of the entire site with each artifact in its original position in color-coded soil layers. Researchers can then look at the site in ways that are impossible in the real world, rotating the model or slicing through it to view cross sections.
GIS also helps archaeologists discover new sites. They use the software to create maps of the geographical characteristics of an area, including elevation, soil type, and distance from water. After mapping each site in the area, archaeologists then search for the kinds of places that they know people of the past preferred. The GIS software then pinpoints places that share those characteristics, directing archaeologists to other likely sites.
Several GIS programs are commercially available, but archaeologists often turn to open-source software to meet their specific needs. "In fact, archaeologists are among the leading developers, proponents, and users of free and open-source software for GIS," says Dr. Scott Madry of the University of North Carolina at Chapel Hill, an archaeologist who studies European prehistoric sites. "We don't have a whole lot of money," he says. "You should never go into archaeology for the money, and a lot of the commercial software tools are very expensive."
GIS helps researchers make the most of time in the field. "For example, I live and teach in the U.S., and my primary research area is in France," Madry says. "It's very expensive for me to get over there and to get a team of students over there; all the travel, all the cars, all the logistics are very expensive. By doing our GIS mapping and our modeling, we're able to be much more targeted and efficient in terms of how we use the time that we have in the field."
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