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by Erin Hatfield Art historian Richard Williams was looking for a non-contact scanning system to capture 3D data from miniature terra cotta, bronze and stone masks that are thousands of years old. The folks from the Rapid Design and Manufacture Centre (RDM) at the University of Glasgow in Scotland introduced him to the Eyetronics scanning system, and the rest is recent history. Williams and his colleagues at the University of Glasgow use non-contact 3D scanning to create digital 3D models of the masks for a virtual archive of terra cotta miniatures on display in museums throughout Europe. The researchers also output the scan data to 3D printers, where replicas of the original masks and larger, life-size versions are made. The project, directed by Professor Elizabeth Moignard and funded by the Arts and Humanities Research Board (AHRB), will pair the virtual archive with videos of trained actors performing the New Comedy plays of ancient Greece and Rome using the life-size mask prototypes. Capturing ancient culture Williams, a staff member at the Institute for Art History at the University of Glasgow, was inspired to do the New Comedy mask project after reading a book by David Wiles and seeing the miniature mask collections at the Art Gallery and Museum, Kelvingrove, Glasgow. The book was among the first to relate the Greek New Comedy masks to the uses and meanings of masks throughout different cultures. After looking over the images and illustrations in the book and other works on ancient masks, Williams thought that 3D imaging would be a perfect way to further explore the masks, both to capture the original artifacts and to use the masks in practical theater work. At the time, there was no widespread means by which the masks could be captured in 3D, scaled up or down in size if necessary, and output to a 3D printer for a physical prototype. But Williams soon heard from his colleagues at RDM about the use of 3D scanning to preserve and re-create artifacts. His previous projects and ideas about the New Comedy mask project led him to explore the scanning options. "We needed a way to conduct non-contact scanning due to the fragility of the original artifact," Williams says. "We also needed something portable and accurate, both of which are met with the Eyetronics system." Williams travels to museums throughout Europe and uses the ShapeWare system from Eyetronics (www.eyetronics.com) to capture 3D data from masks. He sets up a projector on-site that shines a grid onto the object being scanned, which is then photographed using a standard digital camera - in this case a Canon D60. A single shot captures texture data as well as 3D coordinates. The mask is photographed from different angles, with a complete scan of 10 to 15 shots taking about 45 minutes. Data is captured and stored directly on Williams' Apple laptop, backed up on a hard drive, and then duplicated on CD. After all of the scans have been completed for the day, the data is processed off-site using Eyetronics' ShapeSnatcher software and a calibration file, which is captured on-site with the same set-up used to scan the masks. Texture is applied from the photographs taken with the camera, and ShapeSnatcher derives 3D attributes and coordinates based on the deformation of the grid lines on the mask. The different shots of each mask are automatically stitched together in the software and fine-tuned to create one cohesive 3D model. The process takes between two to five hours for each artifact, and the final 3D model contains approximately 100,000 polygons. Final models can be output as STL, VRML, OBJ and other common 3D file formats. "The masks presented problems that would not occur with a typical human face - sharp angles, concavities and edges," says Williams. "I had to be careful of occlusions due to the masks' complexity and be mindful of the holes created for the eyes, nostrils and open mouths. With each, I have to take more shots." Re-creating New Comedy masks Because the scanning process captures texture as well as 3D elements of each mask, the process is ideal for 3D printing. Williams uses the scan data to create a physical 3D version of each mask that can be handled and studied. The data is output to a 3D printer where a water-based adhesive shoots through a powder substance. A physical replica of the digital data is built layer by layer as the adhesive binds the powder. Williams also wanted an objective means by which he could create
a life-size version of the miniature masks. "The main goal
of the project is to examine the cultural traditions of the New
Comedy masks through performance," he says. "Thousands
of artifacts related to masked performances have been discovered
in Europe, but without life-size masks, we had no way to accurately
reenact the New Comedy plays." "We've scaled data to create a life-size model from a mask as small as seven centimeters - masks that used to be thought of as souvenirs of the time period," says Williams. "It quickly became apparent that the masks preserved proper facial ratios." The researchers found that ratios of key features such as ear-to-ear, brow-to-chin and eye-to-eye were so meticulously observed that the life-size masks fit an average face with one centimeter clearance. This confirmed the hypothesis that the smaller mask prototypes were used to transmit the forms around the Mediterranean region. Modern methods for ancient works Williams has collected 3D data from 40 of the more than 150 masks he wants to scan and sees the project expanding. The 3D digital models of the masks are being gathered as part of a virtual museum that will be launched later this year. Visitors will be able to manipulate the models and explore the masks' 3D qualities. Early findings and performances are showcased at the project's web site www.iah.arts.gla.ac.uk/masks. The project has gone one step further by creating usable masks from the rapid-prototyped models. Williams worked closely with Malcolm Knight of the Scottish Mask & Puppet Theatre Centre (www.scottishmaskandpuppetcentre.co.uk) to get performance-ready versions made of the scaled-up masks. Williams settled on the best-preserved miniatures to reproduce on a larger scale. Knight used the full-sized prototypes from the 3D printers to create molds for the masks he was to create. He made about 20 masks and decorated them using different techniques to make them more durable for performance and true to the style of the New Comedy period. "It's a strange feeling to be in touch with a theater style as old as this," says Knight. "The detail the mask and miniature makers were able to preserve gives me a great appreciation for their high level of skill. By using 3D scanning and objectively scaling the artifacts, we were able to get as close a replica of the original piece as possible." Performing New Comedy plays, centuries later These reproductions have been used by a troupe of trained performers to gain a better understanding of how the Greek and Roman New Comedy plays made use of the masks. The plays were directed by Adriano Iurissevich of Venezia Insenca (www.provincia.venezia.it/veneziainscena/). This was his first experience dealing with theatrical works and masks of the New Comedy playwrights. Iurissevich had his cast read through the plays to get a feel for which masks went with which parts. After the masks were decided upon, the performance troupe set about bringing these ancient works to life in the way the Greek and Roman audiences saw them centuries ago. "We had a difficult time with the genre at first," says Iurissevich. "Commedia dell'Arte mask theater, which I am most used to, allows parts of the face to be visible. New Comedy masks cover the entire face, so we had to adapt our style of acting" The actors practiced to find the proper balance of attitude, posture, voice and movement, and gain a strong consciousness of the energy levels needed for each character. In the end, Iurissevich felt the troupe was able to deliver a performance as close to the original as possible. "The ancient texts and masks transcend time better than I originally thought," says Iurissevich. "The masks really heightened the actors' performances and the language." Studying an ancient art Williams expects to travel throughout Europe this year to scan more of the miniature masks, many of which are currently on display in a number of museums. Six prototypes of the masks he already scanned were on display last year at the Banbury Museum in Oxfordshire, England, as part of the "Behind the Mask" touring exhibition organized by the Scottish Mask and Puppet Centre. Visitors were able to handle the miniatures and see two of the masks in life-size proportions. The exhibit was seen by more than 50,000 visitors and featured a video of Iurissevich's troupe performing the New Comedy plays. "By using the 3D scan data to create true, objective replicas,
we've been able to reconstruct the performance style and capabilities
of the masks," says Williams. "Masks that look a certain
way in static situations take on a whole new persona when applied
to a performance. We continue to be awed by the skill and inventiveness
of the Greek and Roman sculptors." ### |
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