3D printers have gained immense popularity in the maker community for fabricating “final” components, but their original purpose was for rapid prototyping in engineering research and development. Instead of having to send every iteration of a design out to a machine shop to fabricate a prototype for testing, engineering teams can quickly 3D print each revision affordably and with a minimal labor investment. But when you have many part revisions that differ only in the settings used to print them, they become hard to identify. G-ID is an app that uses image processing to identify those prints based on their slicing parameters.
3D printing begins with a solid 3D model that was created in some sort of CAD (Computer-Aided Design) or mesh modeling software. That 3D model is exported as a file that contains a representation of the part’s surfaces in space. That 3D mesh is then imported into slicing software that cuts the mesh up into layers and generates g-code commands that the 3D printer can understand. When you slice a model, you can control every aspect of each layer’s creation. For example, you can alter the density of the inner fill of the part, the number of solid material lines that make up the part’s outer walls, the width of the extrusion, and so on.
The G-ID software and app, which was developed by a team of researchers from MIT and the UK’s University of Sussex, Brighton, can look at the surface of a 3D-printed part, analyze that, and determine some of the parameters used to slice the model. It can, for instance, tell the angle of the outer surface fills. If a database of individual part slicing parameters is available, G-ID can identify which of those iterations a specific physical 3D print represents. It is even possible to implement tiny imperfections or slicing alterations to a 3D-printed object that don’t affect its functionality, but which can act like fingerprints to identify that print at a later time. That capability could, theoretically, be used to track the origin of an unknown 3D-printed part, similar to how paper prints leave identifying markers.