When he was a senior at MIT in 1993, Thomas Massie built a computer device that had the bizarre-sounding aim of simulating the sense of touch. He had no idea that just a few years later he would be lining up orders from the likes of Boeing, Walt Disney, and the Mayo Clinic to put his invention to very practical use. "I used the Field of Dreams plan: 'If you build it, they will come," says Massie, founder and chief technology officer of SensAble Technologies (#211).

Massie's key product, Phantom, is a stylus attached to what looks like a desk lamp connected to a computer. Guiding the penlike device, the user can feel the 3-D items on the computer screen. (SensAble's Ghost software relays data to the tiny motors in the stylus, which sends pressure to the user's fingers, giving the sensation of touch.)

Trying out Phantom requires some suspension of disbelief, like that of a first-time scuba diver who can't quite imagine breathing under water. Imagine this: with Phantom and the company's new FreeForm software, you can trace the planes and edges of a block of clay with your fingers and feel its pliant firmness. You can choose a virtual sculpting tool and make a cut, and clay falls away. You can change the texture from hard to soft, from rough to smooth, with a few keystrokes. Your tool can even disappear inside the clay, allowing you to sculpt from the inside out, squirt extra clay like toothpaste, or pull its surface to form gravity-defying shapes.

Jeff Kleiser, co-owner of Kleiser-Walczak, a company headquartered in North Adams, Mass., that creates special effects for TV and film, explains the advantages of the new technology for his business: "When artists make computer-generated characters, they first use clay to sculpt the creature. Then they use a 3-D digitizer to scan it into the computer. With FreeForm you are literally touching the data and modifying it interactively."

Through word of mouth, SensAble has won a following among artists and computer animators, as well as designers, engineers, and scientists of every ilk. Companies including Ford, Hasbro, and Shell apply touch simulation to everything from making toys and shoe soles to conducting "virtual assembly" of engine parts or interpreting seismic data used for oil drilling. John Ranta, a principal at Teneo Computing, in Princeton, Mass., is developing software for use with Phantom that will "create the look and feel of teeth" to enable dental students to simulate surgery, drilling, and cavity-filling procedures. "SensAble has the only 3-D touch technology with this degree of realism," says Ranta.

In another application, 3-D touch allows medical students to try their hand at surgery before they encounter a real patient. In a suture simulation, a flesh incision appears on the computer screen and the elasticity of skin can be felt each time a suture is made by manipulating the stylus.

With revenues of $3 million in 1998, SensAble has come a long way from the days when Massie and his wife, Rhonda, at the time also a student at MIT, were building Phantoms out of their dorm room. "We did everything: we physically took the chunks of metal and cut and welded them. The only thing we didn't do was mine the ore," he recalls. Taking bootstrapping to an extreme, Massie first financed the company with his student stipend. Those early beginnings are a far cry from the business today, which received $7 million in venture capital in 1998 and employs 40 people in spacious Cambridge, Mass., offices. Massie acknowledges that "once you take the venture capital, you cross the Rubicon. It's no longer a lifestyle company--but that's a decision you consciously make going in."

Amy Yee is a freelance writer based in Brookline, Mass.