Reconstruction of Hyaenodon Fossil from Micro-CT


The genus hyaenodon represented part of an order of carnivorous mammals that was dominant from the Eocene Epoch of the Paleogcene Period (Cenozoic Era), roughly 42 million years ago; it became extinct in the Oligocene Epoch, approximately 25 million years ago. Hyaenodon mammals (Hyaenodontidae Creodonta) were distinguished by their hyena-like teeth, large skulls and small brains. Simpleware software was used to help reconstruct a hyaenodon fossil from micro-CT data for 3D printing as part of a long-term paleontological project in Japan and Mongolia. The fossil sample, recovered in Mongolia, included the first and fourth primary molars on the lower right-hand part of the jaw of the hyaenodon, and was exported from Simpleware ScanIP as an STL file for 3D printing and museum display as a multi-part model.


  • Data obtained from a hyaenodon fossil using micro-CT
  • Visualization, manual segmentation and smoothing operations carried out in Simpleware ScanIP
  • Robust multi-part STL file for 3D printing generated in ScanIP
  • Final printed model divided into tooth and jaw sections
  • 3D printed model on display at the Nagoya City Science Museum

Thanks to

Nagoya City Science MuseumNagoya Municipal Industrial Research InstituteHayashibara Museum of Natural Sciences, Paleontological Centre (Mongolian Academy of Sciences), JSOL

Image Processing

Image data of the hyaenodon fossil was first obtained using a micro-CT scanner, before being imported to Simpleware ScanIP for visualisation and processing. The original micro-CT data included a partially blurred tooth section with a concave-convex shape. ScanIP was used to smooth the surface using manual paint and smoothing tools, while a hole present on the top of one of the teeth was maintained in order to better represent the original geometry of the fossil.

Mesh and Model Generation

A watertight STL file was generated in Simpleware ScanIP that could be used for 3D printing. One of the advantages of ScanIP’s ability to mesh from image data is that it can handle multiple parts without errors, enabling a robust STL file to be created of the model without any further meshing required. Refinements were also made using ScanIP to the size and number of triangles for the mesh, optimising the 3D printing process.

3D Printing

The resulting 3D printed model was scaled up to twice its actual size in order to make it easier to visualise the relationship between the molars and the jaw section. The final model was also divided into sections so that observers could better see how the teeth and the jaw fit together. Unlike other fossil exhibits, the printed hyaenodon model can be handled, and can be easily reprinted from the same data-set, with re-scaling and separation of parts also possible.