TEACHING QUALITY RAPID PROTOTYPING OF MACROVERTEBRATE FOSSIL SPECIMENS BY MEANS OF FUSED DEPOSITION MODELING, USING LASER/TEXTURE AND COMPUTED TOMOGRAPHIC DATA

Undergraduate and post-graduate programs in vertebrate paleontology require students to develop a tactile familiarity with fossil specimens. In many cases, important specimens (e.g., holotypes) and reference collections of common vertebrate fossil materials are not readily accessible to students in smaller colleges. While traditional injection-molded casts are usually available, they are relatively expensive to purchase and time-consuming to produce. Desktop rapid prototyping machines, commonly called “3D printers,” offer a quick and affordable means of producing teaching quality replicas of large fossil specimes using Fused Deposition Modeling (FDM). The physical process of producing these models from digital files requires little human interaction, and uses a single nontoxic material (durable thermoplastic; typically ABS or PLA) to accomplish what is typically done manually with liquid silicon rubber molds, releasing agents, liquid epoxy resins (many of which can cause allergic reactions), and vacuum chambers. As affordable FDM printers produce vertical layer heights of 50-100 µm, it is difficult for them to resolve fine imperfections such as fractures in tooth enamel and nano-scale characters like trabeculae. However, smaller scale details such as cutting edges in teeth, foramen, and and pathologies like osteoarthritis and bite marks in archosaur bone can be reproduced with precision. As such, education-grade models of fossil skeletons can now be produced at fractions of the production cost of resin-casted models. The process of creating and fusing these models is relatively simple when planned and prepared in open-source 3D visualization software (e.g., Meshlab, Netfabb) and executed in proprietary printing software, even when using printers with relatively small build volumes. Errors are common in the printing process, though can be avoided with regular maintenance, appropriate materials, and proper system settings. As a demonstration, full-scale rapid prototypes of juvenile Tyrannosaurus rex (BMRP 2002.4.1) and Parasaurolophus sp. (RAM 14000) crania have been produced from laser/texture and CT data, respectively, for approximately $90 USD in total material costs. These models are high quality, low cost, and have already proven effective in educational settings.