SIMPLE-PATCH METHOD IN FOSSIL RETRODEFORMATION AND RECONSTRUCTION

Retrodeformation (reassembly of dislocated elements) and reconstruction (recreation of missing elements) are crucial steps in preparing virtual fossil material for further research, such as finite element analyses and morphometrics, or preparing material for 3D printing. However, damaged or lost elements can hinder data collection and prevent some fossils from being subjected to such methods. To circumvent these issues, we developed the simple-patch method for fossil reconstruction. Simple digital patches can repair and reconstruct meshes (.stl) of fossil material to create a singular solid mesh that can be used in further analyses or be 3D printed. To demonstrate the simple-patch method, we segmented all the cranial elements of a captorhinid stem-reptile Euconcordia cunninghami in VG Studio version 3.0. While most cranial elements of E. cunninghami are present, several feature minor fractures. The right lower jaw in particular is missing multiple elements resulting in a major gap along the lateral wall. All segmented elements were exported as meshes and imported into Autodesk Maya for retrodeformation. Following retrodeformation, square mesh patches were sized and placed to fill minor gaps between bones or sculpted to reconstruct larger missing elements. Once elements were reconstructed, all meshes were combined by shrink-wrapping in Autodesk Fusion 360 to create a singular, simplified mesh. The simple-patch method of fossil reconstruction results in models that preserve an astounding amount of anatomical detail, though some features may be obscured (e.g. suture lines).