Digital or otherwise mechanical ways of reproducing sculpture are becoming increasingly relevant to artists, art historians and heritage organizations alike. In light of this interdisciplinary concern, this article compares nineteenth-century and present-day practices of mapping and reproducing sculptures in terms of geometric ‘data’. It examines a process from the 1830s called ‘medallic engraving’ or ‘anaglyptography’, pioneered by engineers such as Achille Collas, for transposing sculptures’ shapes on to flat printing plates. Examples of this process are compared with the work of contemporary artist Toby Ziegler, who responds to historic sculptures using digital technologies such as 3D printing, and who elaborates on his practice in an interview. In different ways, these nineteenth- and twenty-first-century practices both highlight the inevitable failure of geometric schemata to reproduce the experience of real sculptures. By the same token, however, they also reveal spaces for idiosyncrasy and creativity in even highly schematic forms of reproduction.