This year 2009 contains two significant anniversaries within the scientific community: the bicentennial of Charles Darwin’s birth and the 150th anniversary of the publication of his groundbreaking book On the Origin of Species. To honor these milestones, the National Academy of Sciences (NAS) commissioned the reproduction of a rare bronze bust of Charles Darwin located in New York City for display at their facility in Washington DC. For this challenging task, they contracted John Milner Associates for project management and Direct Dimensions (DDI) for the technical effort.
The original sculpture was fabricated over a hundred years ago by the New York Academy of Sciences (NYAS) to mark the 100th and 50th anniversaries, respectively, of Darwin’s birth and famous book because Darwin was then, and probably still is, considered one of their most famous members. Though Darwin had already passed away in 1882, sculptor William Couper used rare photographs to aid in the creation of his very life-like bronze bust.
The original sculpture resides today in the NYAS office at 7 World Trade Center and is a highly valued museum-quality piece. While the organization was more than willing to allow for the recreation by the NAS, they were not willing to let the rare piece out of their facility where it could be damaged during the mold-making process, or during shipping. Thus to recreate the bust without movement, or in fact any direct physical contact, the NAS contracted John Milner Associates (JMA), a firm that specializes in historic preservation services, to manage this effort.
The JMA team proposed a combination of 3D laser scanning and computer-controlled machining. Laser scanning can make the digital “copy” of the bust on-site at the New York office with no physical contact other than a beam of light. Computerized machining then uses this 3D digital data to mill the ‘copy’ into an exact physical form. The milling is then used as a pattern to cast the new bronze reproduction.
JMA and DDI have worked together for several years on numerous projects involving 3D scanning for historic preservation.
Earlier this year, DDI technicians Peter Kennedy and Jason Page drove to the NYAS office at 7 World Trade Center where they spent the day scanning the original bronze sculpture using a laser line scanner mounted on a Faro Arm. This equipment captured the exact shape and contours to an accuracy of about a tenth of a millimeter. Then back in Baltimore over the next few days, the DDI team used Innovmetric’s PolyWorks Modeler software to process the raw laser data into the 3D digital replica.
The final model, completed in “watertight” STL format, was used in the milling process to create the physical copy of the bust. In addition, this digital data can also be used to visualize the famous Darwin bust in 3D across the internet and to make digital renderings of the piece.
To complete the reproduction process, the milled foam copy, or pattern, was hand-finished by an artist and sent to an art foundry where it was cast in bronze using techniques similar to those used to create the original over 100 years ago!
The final reproduction of the Darwin bronze bust was unveiled in early 2009 at the National Academy of Sciences in Washington in honor of Mr. Darwin’s 200th birthday.
November 24, 2009 is the 150th anniversary of On the Origin of Species.
Visit the National Academy of Sciences website for more information.