International Sculpture Center

   


Sculpture May/June 1998 Vol.17 No. 5

Three-dimensional output technologies, initially developed for industrial processes, are now being applied by sculptors to the making of artworks.

Printing in 3D: Digital Sculpture by George Fifield

Z Corporation's Z402 3-D Printer

Recently, there have been some startling advances in the production of three-dimensional objects from digital files. In the field of "rapid prototyping," printers called "concept modelers" are a new development with great potential for artistic projects. For years, three-dimensional computer-aided design (3-D CAD) software has existed which designs and models three-dimensional forms within the computer. Now, rapid prototyping machines can create actual objects from these files. These machines have great economic potential for industry and fields like medical imaging. By using all-digital technologies for production or design, instead of printing out plans and having these pieces machined by hand, it is estimated that industries like toy manufacturers and tool designers could reduce their development times and tooling costs by as much as 75 percent. As a result there has been a bit of a gold rush mentality these days to develop useful digital 3-D output technologies.

While most commercial rapid prototyping systems are large, expensive processes suitable for a manufacturing environment, a new generation of smaller office modelers has been developed to provide quick feedback during the design process. The office versions also offer inexpensive and interesting solutions for sculptors. The potential for creating artwork has just begun to be explored. These machines are immediately useful for production and scaling by sculptors, but when they are combined with other 3-D input devices like 3-D scanners and virtual sculpting tools, they hint at a digital revolution in which sculpture, photography, and printmaking will all join together.

All of these machines accept computer files with an .STL suffix. That means that they work with most of the 3-D CAD programs on the market. Designers and sculptors could create wire-frame models in their personal computers and modem the files to their service bureau, where an operator could press "print" to produce the object in a matter of hours or even minutes. The 3-D printer has already found acceptance within the medical profession. CAT Scan and MRI files can be translated directly into .STL files. Though MRI files are large, in the realm of over 100 megabytes and take several hours to print out, doctors can generate accurate, scaled-down models of tumors and bone tissue to examine prior to surgery.

These 3-D printers are now being used by artists. Michael Rees, a sculptor in Kansas City, Missouri, and Ralph Helmick, a public sculptor in Newton, Massachusetts, have both worked with rapid prototyping companies to explore the use of the 3-D printer as a sculptural tool. In the future, Rees says, "There is no reason why rapid prototyping shouldn't be at Kinko's and should be inexpensive and easy."

Michael Rees, Ajña 1, 1997. Epoxied powder and painted wood, 59 x 28 x 22 in. Dan Wayne

Rees has a completely digital studio. At present he works solely in CAD software to create his sculptures. He explains one appeal, "While rapid prototyping is expensive, you don't need to have a [large] studio or materials." Over the years he has used six different rapid prototyping technologies and says that they all have their own special qualities. Rees, who exhibited in the 1995 Whitney Biennial, feels that with CAD programs he can make any sculpture he wants. In a recent show, "Digital Psyche," at the Kemper Museum of Contemporary Art in Kansas City, all but one of the five sculptures in the show were made with Z Corporation's 3-D printer. The files were sent by modem to a service bureau, Creative Technical Solutions in Indianapolis, Indiana, and printed there. The other piece was made with a more industrial rapid prototyping process called laser sintering.

Because the digital work is instantly scalable, Rees says, "I can imagine an object's build envelope [as being] eight inches or eight feet." His next show, in May at Grand Arts in Kansas City, will have large work generated directly from CAD files by a new large-scale rapid prototyping system. "Working in CAD," Rees says, "is closer to the thought of sculpture than any process imaginable. It is a language within which whatever one can describe, one can build. The ability to visualize complex structures within structures without the constraints of the properties of those objects is extraordinary. For example, I can't put a tomato inside of a rock and see them both, I can only imagine it. In CAD, the tomato is in the rock."

In their first use of digital printers, Helmick and his associate, Stuart Schechter used a full body scanner to scan two-foot-tall clay maquettes of a memorial to Jackie and Mack Robinson which they were commissioned to create for the city of Pasadena. They sent the file by modem to a 3-D printer in another city. There, a number of two-inch copies were printed out for a quarter-inch to one-inch site model as well as some three-quarter-inch copies for smaller scale models. Helmick notes that, "the 3-D printers saved us one whole step" by translating their work into different scales.

Ralph Helmick, Stuart Schechter, and John Outterbridge, "The Jackie and Mack Robinson Memorial", 1997.

Bronze, (each head) 104 x 67 x 80 in.

This year, Helmick has received a commission for which he will use the Z-Corporation's 3-D printer in the final process. He and Schechter have started on an interior commission for the East St. Louis Federal Courthouse. In a multi-story central space, they will suspend hundreds of copies of 12 small heads, representing the American jury, at various points along numerous coated aircraft cables suspended from the ceiling. The smaller heads will be used to create two multi-story heads representing an Asian-American woman and an African-American man. They will model the original 12 heads, life-size, out of clay, then scan them and print out the reduced versions. Then they will use those three-dimensional "prints" to cast multiple metal reproductions. The Z-Corporation's output lends itself to investment casting as the wax-coated cellulose it is made of burns out under heat with a minimum of ash.

Besides the Z402 3-D printer by Z Corporation of Somerville, Massachusetts, the most intriguing "concept modelers" are the Actua 2100 system by 3D Systems, Inc. of Valencia, California, the Genisys system by Stratasys, Inc. of Eden Prairie, Minnesota, and the ModelMaker II System by Sanders Prototype, Inc. in Milford, New Hampshire.

The Z Corporation machine uses a powder technology developed by M.I.T. to build its objects. It lays down material like a laser printer. It builds the positive form with a cellulose (carbohydrate) powder which binds together as it is built up in layers and it fills the negative space with an inert powder that does not fuse. The completed object is then removed from within a cube of the fine dry powder when finished. It is the quickest and least expensive of the machines.

After printing, the objects can then be soaked with wax or epoxy. When soaked in wax, they can be used in a lost-wax process for investment casting with many materials, including bronze or aluminium. The cellulose and other powders are non-toxic and cost about 65 cents per cubic inch. The largest size this machine can print is about eight inches by eight inches by ten inches, built up in layers of one-seven-thousandths of an inch. An interesting result of this process is that there is no time penalty for complexity. A complicated shape with many internal twists and turns is printed in the same time as a solid block of the same size.

The other concept modelers use spray nozzle technology, similar to an ink jet printer, to build up their objects. Because there is no negative space support, these machines must build additional support structures within the objects. The Genisys system produces models from a high-strength polyester compound which it sprays from an extrusion nozzle. The parts are sturdy, but because they are polyester, they are not usable for investment or lost-wax casting. The support structure it builds while being constructed is easily broken off of the part. The Genisys resolution of .013 of an inch is a bit coarse. The Actua 2100 uses a thermo-polymer (wax) material, called ThermoJet 65, to build its parts. It also builds its models using a technique like ink jet printing, applied in three dimensions. Ninety-six jets oriented in a linear array build up the models in successive layers. The surface may be very rough and needs a lot of work to finish it, mostly because of the support structure. The thermo wax is also quite brittle, but it is very good for casting.

The machine with the finest resolution is, not surprisingly, one of the slowest. The ModelMaker II System by Sanders Prototype enjoys an incredible one-half-thousandths of an inch resolution. It also uses a thermo wax which is very good for lost wax casting and can be used for delicate parts like jewelery and pieces with fine detail. Its largest size is twelve by six by nine inches.

These machines come with software that is often capable of improving the final object by rotating it within the build envelope (the maximum scale for the printer) to minimize "stair-stepping" of layers, which occurs on diagonal surfaces during the printing. Parts may be also moved, copied, and deleted by the software before printing.

Objects may also be scaled by the software. Changing scale has always been a laborious task for sculptors. But besides convenience, scale has great power as an aesthetic force. Helmick, for instance, is enthusiastic about using software scaling to create sculptural perspective. He describes his desire to print an object with a 3-D printer, then scale it down 95 percent, print that, scale it down again and on and on. By lining up a series of these pieces, it would appear that they are getting larger as a viewer moves toward them. Nick Capasso, associate curator at the DeCordova Museum and Sculpture Park in Lincoln, Massachusetts, is hopeful that, "If scale becomes effortless, it will encourage more artists to consider scale as an aesthetic device."

Capasso is also intrigued by the issues concerning the speedy reproduction of objects that these machines allow. Without casting, exact reproductions of identical objects can be made as long as one keeps supplying the machines with material. "If you can have 500 identical objects without having to sweat, that opens up a world of possibilities about sculptures that have to do with the idea of sets, sculpture that relies more on the interrelationship among a set of related objects than on the formal properties of a single unitary object." Capasso explains that, "this has been done before but [these systems] make it so much easier."

Three-dimensional body scan, printed on the Z402 3-D printer. Starch, cellulose, and wax, 9.5 in. tall.

Mark Teatum/De Cordova museum and Sculpture Park, Lincoln, Massachusetts

Combined with new technologies that are able to scan and input three-dimensional surfaces into the computer, these printers become part of the larger digital world. Three-dimensional scanners that map the exterior surface of an object or a person by "reading" them with lasers and then generate an .STL file are already prevalent. Some are even big enough to map an entire body. Printed out, these reduced files of heads, whole bodies, or objects represent three-dimensional photography. These files of scanned objects and body parts can be easily collaged within the computer. As photography changed the meaning of painting, three-dimensional object photography will change the role of the artist's hand in traditional sculpture. Realistic sculptural representation entails a sense of great effort. With 3-D object photography the issue is only one of resolution.

New digital software is already being developed to add a handmade look to the perfection of the printed 3-D object. Today, you can pass digital video through filters that add faux film scratches and film tones to it. It is also easy in Photoshop to add, for instance, a watercolor effect filter to a scanned photograph. In the 3-D CAD environment, there are ways to input images, besides scanning, and use them for displacement shading or other modeling. Michael Rees adds his fingerprints, in this manner, to all of his CAD images before printing them out. Sometimes he enlarges his fingerprints and they become an element of the surface design.

We bring our memories of working by hand into the digital world. "As a result of this," Rees says, "that wonderful weightless environment of the computer, [which] to me is akin to dream space, is informed by the real world metaphors of building, weight, and gravity."

George Fifield is the adjunct curator of media arts at the DeCordova Museum and Sculpture Park and director of VisionSpace, Inc., which is planning the 1999 Boston Cyberarts Festival. His e-mail is <gwf@tiac.net>.

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