If you take enough pictures from enough angles, you can use photo-stitching software and a 3D printer to produce a duplicate of a sculpture. Cosmo Wenman demonstrates the process in this video:
Once one person has done this and posted the specs online, anyone with access to a 3D printer can make more copies. Or you can make adjustments to create your own derivative works.
Virginia Postrel's latest column explores the implications. Here's an excerpt:
The technology is still primitive and frustrating, and the scans it produces are far from perfect, but the future is clear. The masterworks of three-dimensional art are joining the digital commons. For art lovers, this technological moment represents a tremendous opportunity. The combination of digital scans and inexpensive 3-D printing could do for three-dimensional art what prints have been doing for paintings and drawings for 500 years: make these works familiar, beloved and visually influential to people who will never have a chance to see them in person.
"If you're an art teacher who can get your hands on a MakerBot, you can now create a section of the Met that you can have in your classroom to inspire your students," says Bre Pettis, the co-founder and chief executive officer of MakerBot Industries and a former middle-school art teacher in Seattle. It's a chance, in Wenman's words, "to spread faithful reproductions of treasured artwork far beyond the walls of elite palaces."
The question is how the elite palaces will react. Will the institutions that own the originals encourage making data maps public? Or will museums try to lock up the digital versions of their treasures, so that duplication becomes a pirate activity? Attempts at the latter might ultimately fail, but they would still slow down and stigmatize a process that could greatly enhance the value of the world's artistic heritage.