EXPLORING PALEOICHNOLOGICAL AND NEOICHNOLOGICAL APPLICATIONS OF THE FREE DIGITAL CAPTURE SOFTWARE AUTODESK 123D CATCH

Autodesk 123D Catch is freely available for PC, iPhone, iPad, Android, and as a web-based application. The software uses photogrammetry to create 3D digital models from still photographs taken either with the camera built into the mobile device running the application or with a digital camera and uploaded through the website. Ichnological applications of digital models include quantifying such difficult-to-measure properties as volume and surface area, visualization of complex 3D architectures, preservation, teaching, and outreach. My goal is to explore 123D Catch 3D model resolutions and fidelities using different digital capture methods. Captured models range in size from mm-scale trace fossils on bedding planes to entire outcrops. Scanned traces include examples of Treptichnus, Arenicolites longistriatus, and Attenosaurus from the Pennsylvanian Pottsville Formation, Steven C. Minkin Paleozoic Footprint Site, Walker County, Alabama, Gyrolithes from the Eocene Tallahatta Formation, Grenada County, Mississippi, casts of theropod dinosaur footprints (cf. Eubrontes) from the Cretaceous De Queen Formation, Howard County, Arkansas, and plaster casts of modern armadillo foraging pits from soils in Lafayette County, Mississippi. Preliminary results show a wide range in model resolutions (measured as mesh vertices/cm²). Distance from the subject during photography plays a large role in determining the final resolution of the 3D model. The highest resolution produced so far is 459 vertices/cm²; this is an order of magnitude lower than the resolution typical of models produced with the relatively inexpensive NextEngine laser scanner. The resolution of the 123D Catch models is suitable for capturing overall architectures and geometries. In some examples, models captured with an iPhone were higher resolution than models photographed with a high-quality digital SLR camera. Scale is not preserved in 123D Catch digital models so all imagery must include scale bars and resizing is necessary with post-processing software, e.g., Blender. Such small-scale features as a ~1 mm diameter Treptichnus and the surficial striations of A. longistriatus were too fine to be captured. Finally, highly contrasting colors on the flat surface of a scale bar can introduce artificial topography (< 1 mm high) in the 3D model.