An archaeologist needs a way to study clay pots after they are returned to Native American burial grounds. A biologist wants to help visually impaired students understand microscopic data. A sculptor wants to create “napkin sketches” in three dimensions. Different researchers. Different problems. One solution—PRISM.
PRISM is the Partnership for Research In Stereo Modeling. The project encompasses the entire spectrum of disciplines at Arizona State University, linking scholars from fine arts and design, the sciences, engineering, and the social sciences. Work in PRISM laboratories allows members of the ASU community to record, manipulate, and recreate three-dimensional data using some of the most advanced technology available today.
The possibilities are boundless. Any three-dimensional object, from a tiny red blood cell to an entire person, can be recorded into a computer file. A scanning device traces the object’s surface geometry and records its precise shape on a computer using x, y, and z coordinates.
A student or scientist can view the object using cutting edge 3D modeling software designed by the PRISM researchers. The software lets users rotate the object and view it in several formats. In addition, users can manipulate the data—scaling, stretching, or twisting the object on-screen. They also can combine scanned data with computer-generated data.
The most exciting prospect of PRISM may be the ability to generate a 3D model of the computer data—a kind of 3D printout—using a rapid prototyping machine. The machine actually builds the model layer by layer using a melted polyester material.
The process is similar to the way an inkjet printer lays down ink dot by dot. Each polyester layer is only .007 inches thick, allowing for a high degree of precision in replicating the original object.
Currently, researchers at the PRISM lab can produce models in polyester, ABS plastic, or investment casting wax which is used for creating molds. In the future, the PRISM team hopes to broaden the spectrum of materials available for prototyping.
Laying the Foundation
The technology behind PRISM is complex, but the founder of the program has little technological background. Dan Collins is a professor of art at ASU. He simply wanted to find a way to make better sculptures.
“During the late 80s and early 90s I was involved with a process called anamorphosis,” Collins says.
Anamorphosis is a technique for abstracting images. For example, an artist might stretch an image so that it is unrecognizable when viewed from the front, but recognizable when viewed from an extreme angle.
The technique has existed for centuries. Collins is working to bring it into the three-dimensional world and to apply it to new media, like video.
“Early in that process it became clear to me that I would need some pretty heavy computing power in order to pursue this,” he says. “I did some research into the new field of 3D laser digitizing. I called all over the country to find systems that would do what I wanted it to do. I’m an artist. I don’t have a technical background. So I was asking some dumb questions,” Collins laughs.
Eventually, Collins hit pay dirt with a company called Cyberware located in Monterey, Calif. Cyberware officials invited him to visit and try out their equipment. Experimenting with the technology was vital for Collins.
“It’s one thing to walk into a service bureau and say, ‘Please make me a 3D scan of this object,’” he says. “It’s another to really play with the technology and test its limits, to try things that aren’t supposed to work.”
For example, when Collins decided to do a full-body scan of himself, the technologist working with him warned him not to move. But the artist wanted to know what would happen if he did move. So he built himself a large lazy susan, had his wife spin it while he stood in the middle, and then scanned himself. The result is a sculpture Collins calls “Twister.”
Collins was smitten with the technology. He wanted to bring it to ASU. However, he realized that such an enormous and expensive undertaking required the support of more than one department.
Collins took the traveling salesman approach. He knocked on doors across campus.
“I visited different offices and asked for artifacts. I took suitcases of objects to Cyberware—everything from bones to industrial design projects to mechanical engineering models. Then I scanned them. I was always dragging people over to the lab and asking, ‘Is this useful to you?’ People got very excited.”
Ideas and enthusiasm alone were not enough to make PRISM a reality. The project required a hefty dose of technical expertise. Early in his quest, Collins teamed up with Gerald Farin, an ASU professor of computer science and an expert in computer-aided geometric design.
He also hooked up with Mark Henderson, an engineering professor and former director of ASU’s Computer Integrated Manufacturing Center, and Anshuman Razdan, an engineering doctoral student. Together, the four men now make up PRISM’s core team.
Razdan says that support for the project has been overwhelming.
“There was such an outpouring of support from people in archaeology, anthropology, biology, materials science, art, architecture, as well as from the traditional engineering department,” he says. “One of our first goals was to place the project under the Office of the Vice Provost for Research. We wanted it to be free of any department or college territory. We really wanted the project to be an interdisciplinary laboratory.”
And so, in 1996, PRISM was officially born. Currently, at any given moment, 20 to 25 faculty members from different departments conduct research using PRISM facilities.
Scanning the Past
Charles Redman is an archaeologist and professor of anthropology. He uses PRISM technology to preserve artifacts that soon will be lost to archaeologists forever.
The Archaeological Research Institute (ARI) at ASU houses a collection of important artifacts recovered during construction of Roosevelt Lake. The objects were created by a Native American tribe now known as Salado. The Salado people were one of the more sophisticated tribes in the central Arizona region. They reached the height of their civilization about 600 years ago.
Archaeologists use these artifacts to study the Salado. However, very soon ARI scientists must return the objects to tribal descendants as a result of the Native American Graves Repatriation Act. The federal law returns authority over native burial artifacts to the tribes’ biological descendants. Most of these objects are reburied in the ground where they were found.
“These objects are being removed from future studies, probably forever,” Redman says. “This presents a very difficult situation for archaeologists, because it eliminates a large number of objects from new technologies, future studies, and approaches we don’t know today. This is made more urgent by the fact that objects interred with the dead often have special meaning. They often are the most complete objects.”
Before returning the objects to their rightful owners, Redman and his ASU colleagues are digitizing them in computer file form so that they will be available for future study. It’s a win-win situation.
The laser scanner in no way affects the objects. Each one will be returned to descendants of the Salado intact and unharmed. While the original objects are put to rest in their proper place, archaeologists can still study them using the computer. They also will have the ability to produce as many replicas as they desire.
The urgency of the Salado project made PRISM a priority for Redman. Eventually, he would like to scan all of the ARI’s collection.
“Some objects disintegrate. Others disappear or erode because they’re not made of very stable organic materials,” he explains.
Redman says that recording artifacts digitally is important for several reasons. First, the data can be shared over the Internet. Researchers from all over the world can study objects without traveling to them. And there is no need to transport objects, risking further deterioration.
Categorization also can become more precise. Shapes can be classified using a mathematical formula rather than a scientist’s subjective observation.
Such precision may be important as archaeologists develop new techniques for analysis that current researchers cannot even imagine. The 3D scan will provide complete information about the objects, including information that may not be considered important today.
“We want to study with greater precision. We want to ask questions that haven’t been asked before about the appearance of an object. We’ll want to use that information in ways that I can’t foresee today,” Redman says.
Touchy Subjects
PRISM provides scientists the ability to scale 3D data, another powerful feature. Using a scanning probe microscope, researchers can record data on an atomic scale and produce an enlarged replica visible to the naked eye. More importantly, students who cannot see can hold and feel the object to understand its shape and proportions.
“Typically, blind students are discouraged from entering the sciences,” says Razdan, now the technical director of PRISM. Science is difficult for visually impaired students because so much of the work relies on vision.
“Microscopic images are viewed by eye, usually through a series of glass lenses. More sophisticated microscopes use lasers to scan the image which is displayed on a computer screen. Either way, blind students cannot see it,” he says.
Razdan is lead investigator for the “Scientific Visualization Using Tactile Feedback” project. The work is an effort to create educational models for the visually impaired.
“We want to devise some sort of tactile model that is not an artist’s rendering, but actual data itself,” Razdan says.
The team has extended its horizons beyond microscopic data. Co-investigator Veronica Burrows is a professor of engineering. She produces models of phase diagrams, commonly used in chemistry classes. Instead of scanning an existing object, Burrows generates the model from computer data. Students place a metal crosshair along tick marks on the diagram in order to interpret the data.
In the future, tactile modeling could be used to help students study almost any subject, not just the sciences.
Razdan hopes that tactile models will become a regular component of classroom materials. “If toothpicks and balls [used to build models of molecules] can become popular in chemistry classes, there’s no reason this can’t work even better,” he says.
Razdan believes that tactile modeling is helpful even for students who can peer through a microscope. “Some sighted people have trouble with the three-dimensional image projected on a 2D screen,” he says.
“These atomic things are hard to visualize, even for people who have vision,” adds B. L. Ramakrishna, co- investigator and director of the scanning probe microscopy program at ASU.
“The scanning probe microscope works in a tactile mode. It touches and feels the surface of the object. Now, these people are actually touching and feeling the surface, too. It brings a nice closure. You’re converting it back to tactile data and letting your fingers do the walking.”
Stretching Data
Former ASU graduate student Carl Dahl wanted to let his fingers do the walking in a different way. A student of fine art and computer science, Dahl approached Collins with the idea of creating a computer modeling tool for sculptors. The resulting project is called Hand-Eye Relational Analysis (HERA). The actual tool includes a virtual reality-type glove that lets artists sculpt in virtual clay.
“It’s totally interactive, like pulling taffy,” Collins explains. Razdan says the process is much like “a napkin sketch in 3D.”
HERA has one large benefit. Sculptors never run out of virtual clay. The artist can stretch it indefinitely without fear that it will break or tear. HERA’s potential also stretches well beyond the confines of ASU art studios.
“There are many exciting applications. Beyond making cool forms, HERA can be used to track the developmental progress of young kids as they proceed through an art experience,” Collins says.
“We’ve done some initial work with an art educator. He’s in the business of looking at developmental levels of small children in terms of spatial awareness,” he adds.
Collins hopes that technology such as HERA will be made available to the community in the near future.
“As the cost of technology goes down and quality of the interface improves, these tools are really going to impact how we teach young artists.”
Beyond the Ivory Tower
Art education is just one way PRISM researchers are reaching beyond the ivory tower and into the community. Local schools and businesses also are getting the opportunity to share this extraordinary technology. In return, they share their expertise and feedback with ASU scholars and others.
Arizona businesses have taken advantage of PRISM’s capabilities. The PRISM Advanced Rapid Fabrication Consortium (PARfC) is one example. Razdan says that PARfC was created to establish a cutting-edge research facility that also provides educational opportunities. It also serves as an outreach center, demonstrating new technology to companies large and small. Consortium members include Motorola, Allied Signal, Boeing, Raytheon, Phoenix Analysis and Design Technologies, and Toytime, Inc.
“We want to be a listening post for industry,” Razdan adds. “We also are building an advanced knowledge base. Share the cost and you share the reward. We learn from each other’s projects. The ASU community benefits in many ways, because we expose faculty members and students to real world projects.”—Diane Boudreau
