Classically trained sculptors breath new life into four 20-foot angels with the help of Rhino.
When Old Structures Engineering engaged Boston Valley Terra Cotta in the restoration of the 1896 vintage Beaux-Arts building at 150 Nassau Street in New York—one of the city’s original steel frame structures—the four decorative angelic figures, or seraphs, that adorned the corners of the uppermost story were in serious decay. “Up close, they were in an appalling state,” said Andrew Evans, engineering project manager. “The biggest issue we had with the angels was understanding what happened with the originals.”
The seraphs were carved from stone by Spanish immigrant Ferdinand Miranda in 1895 and had suffered years of exposure and improper maintenance. By the time the facade was up for rehabilitation, the angels were haphazardly strapped to the building with steel bands and supported with bricks. Their state was such that repairs would not suffice and Boston Valley’s artisans began the task of recreating the 20-foot-tall Amazonian figures.
It was the company’s first foray into parametric modeling. Like Dorothy stepping from sepia tone into Technicolor, the sculptors at Boston Valley Terra Cotta proclaimed, “We’re not in Kansas anymore,” when they fabricated the 20-foot angels using parametric modeling and lasers. “I have a history in classical sculpture, so when this came in front of me, it was sink or swim,” said Mike Fritz, master sculptor at the Buffalo, New York–based ceramics company. “We went to Oz and everything changed after that.” Henceforth, the newly constructed terra cotta angels came to be known as “Dorothy.”
The most decrepit angel was photographed onsite and then disassembled for shipment to Buffalo. In Boston Valley Terra Cotta’s ceramics studio, the images were converted with photogrammetry software and transferred to Rhino to build a digital model. The model was divided into sections, such as an arm, a face, several feathers of a wing, etc. Then a laser cutter was used to cut plywood profiles that matched each section.
“Those [plywood] profiles of her face or her arms were packed with clay to realize the full forms,” said Mitchell Bring, the project manager for Boston Valley Terra Cotta. Each of Dorothy’s parts were hand-finished by Boston Valley’s staff of 30 sculptors. Once the clay had set, negative molds were made of each section to form the parts for Dorothy’s identical sisters. The finished sections, each of which weighs upward of 500 pounds, were shipped back to 150 Nassau Street in pieces and assembled onsite with mortared joints.
Since completing the project, the digitally enhanced sculpture methods have been refined and wholly embraced by Boston Valley’s team of artisans. “Through this work flow, we’re able to get a little closer to our material earlier in the process,” Fritz said. “If we went without the new tools, it would have been six weeks of work in total. But even with our substantial learning curve the modeling and the build on the shop floor only took two-and-a-half weeks total.”