The sign's message was clear enough: Please Do Not Touch. For some visitors, however, the temptation was too great.

Here at the recent Maker Faire, a traveling festival for technology enthusiasts, people ran their fingers over the car's ribbed exterior. The bolder ones took a more brazen approach, knocking their fists against the surfaces to see how the material would respond.

One eager young boy, all of about three feet tall, went further, licking a front fender to learn how it tasted. A mortified parent quickly admonished him.

This irresistible attraction was a 3-D printed vehicle made by Local Motors, and interest at the New York Hall of Science in Flushing Meadows-Corona Park in Queens was intense. Bystanders crowded around, closely inspecting the car's structure, which combines the body and chassis in a single unit and is made entirely from a composite, acrylonitrile butadiene styrene, reinforced with carbon fiber. Commonly called A.B.S., it is the same thermoplastic used to make Lego bricks.

The process known as 3-D printing has gone through a meteoric rise in popularity in the last five years, spurred by the emergence of low-cost printers and easy-to-use software. Home hobbyists can print items like iPhone cases, coffee mugs and semiautomatic rifles.

For companies like automakers, recent innovations in large-scale 3-D printing have advanced their capabilities for rapid prototyping, fueling innovation and potentially lowering production costs.

Local Motors, a Phoenix-area innovator of many forms of vehicles, built this 3-D printed creation, called the Strati, in partnership with the Oak Ridge National Laboratory, the Association for Manufacturing Technology and Cincinnati Inc.

"The goal here is to get the number of parts down," said John B. Rogers Jr., chief executive of Local Motors. "Cars are ridiculously complex.

"Everyone knows that the supply chain is a gargantuan process," he added, referring to the many suppliers that provide the bits that make up modern vehicles.

Local Motors began the project in April with a design contest aimed at producing a car that would take advantage of 3-D printing technology. The company received more than 200 submissions, eventually choosing a design by Michele Anoè, an Italian automotive designer. Mr. Anoè named his entry Strati — Italian for layers — because of the elaborate buildup process used in 3-D printing.

After months of preparation, which involved testing the viability of large-scale 3-D printing, the Strati came to life this month at the International Manufacturing Technology Show in Chicago. All the printing, done on a printer about the size of a shipping container, was completed on-site in Chicago in 44 hours, with a team from Local Motors finishing the assembly by sanding and shaping the body for a better finish and by fitting the mechanical components to the body. The entire process took about four days, Mr. Rogers said. (Assembly video.)

The car consists of fewer than 50 parts, the company says, including a 45-kilowatt electric motor and a transmission donated by Renault, along with headlights, taillights, wheels and a steering column bought from other manufacturers.

Mr. Rogers said the idea for the project was focused on the development of a production process that incorporated various components of 3-D printing. "When you use direct digital manufacturing, the tooling cost drops to almost zero," he said. "We believe there is no better way to retool something."

Large-scale 3-D printing is a relatively new process, but has the potential to be used in an array of industries, including aerospace, according to James Earle, an engineer at Local Motors. Mr. Earle says the printing process is similar to the operation of a hot-glue gun, beginning with solid thermoplastic pellets that are heated and then extruded in liquid form through a nozzle. The nozzle, moving like the head of a computer printer, adds layer after layer of material in thin strips until the object is complete, resulting in something of a corduroy surface texture.

"We have said publicly that the price could be $18,000 to $30,000 for the Strati," Mr. Rogers said. Early versions will serve as low-speed runabouts, a vehicle class known as neighborhood electric vehicles.

In all, Local Motors says it has spent less than $1 million to bring the Strati project to fruition, and it will invest more to streamline manufacturing.

"We are currently printing at 44 hours per Strati," Mr. Rogers said, "and we hope to continue to lower the time it takes to print."

The idea of vehicles being pumped out on large-scale 3-D printers may sound alluring, but it also comes with significant, and perhaps insurmountable, roadblocks.

In a brief low-speed ride on paved paths in the park, the 2,200-pound Strati hummed quietly and handled bumps surprisingly well. When asked what would happen in a crash, though, Mr. Earle, driving the two-seat car, said it would be like a rock slamming against a brick wall.

The thermoplastic used on the Strati is not stronger than a metal counterpart per weight, Mr. Earle said. "These composites allow us to do a lot of cool stuff where you can get a high-strength plastic that is much lighter than its metal counterpart could be. We're not there yet, because this technology is really at its birth."

The Strati can reach speeds nearing 50 m.p.h. and travel up to 62 miles on a charge, according to Mr. Rogers, who expects to be taking orders for 3-D printed vehicles in the next 12 to 18 months.

"Safety is the biggest question," Mr. Rogers explained. "Our intention is to make this vehicle safer than comparable vehicles. We are aiming for physical crash results that will be as safe, if not safer, than current vehicles."

Mr. Rogers said that 3-D printed vehicle structures could be made safer by including additives to the thermoplastic that would improve crash-test performance. It would also involve modifying the computer instructions to the printer and adjusting the material composition and thickness based on crash-test results.

"Basically, I am insisting that we as a world don't make the safest car we could possibly make," Mr. Rogers said. "We know it can be done better."