Rivera’s towering warrior, under construction at Additive Workshop

You want a statue. Not just any statue, but a 20-foot-tall bare-chested Native American warrior on horseback. Who do you call?

For acclaimed sculptor George Rivera, whose work stands outside the Smithsonian’s National Museum of the American Indian and in other prominent places, the answer lies in a warehouse space behind the drab car dealerships of exurban Wilsonville. There, a company called Additive Workshop has garnered a lustrous reputation for its dramatic ability to supersize (or shrink) objets d’art.

Rob Arps started Additive in 2005, after graduating from the University of Oregon armed with a fine-art degree and growing frustration with the long, slow work required to take a sculpture from conceptual model to full-scale piece. After teaching himself engineering and robotics, Arps, now 42, patched together a system of high-resolution scanners, 3-D printers, and giant-armed drilling and cutting robots. The company does work for Rivera and many other clients, maximizing the miniscule and slicing many materials into three detailed dimensions.

Additive uses a $150,000 scanner originally developed for aerospace engineering to scan a small physical prototype. (For Rivera’s The Great Horse Dispersement, ultimately bound for a Santa Fe casino, the company sent a team and scanning equipment to New Mexico to capture Rivera’s 26-inch-tall original. The firm more typically brings models to its workshop.) This creates a minutely detailed 3-D digital rendering, which can be blown up or shrunk down to virtually any scale. Tools like a seven-axis robotic cutting machine use the virtual image as a blueprint to carve massive component parts: a horse head as tall as a human, for example. Assembly and finishing details are accomplished by hand, with final touches left to the original artist.

“Our scanning system is a bridge from the tangible world into the virtual,” Arps says. “Once in the virtual, one can manipulate an object in every conceivable way and bring it back into the tangible.”