The present disclosure relates to systems and methods for searching a machining knowledge database that includes stored 3D models and associated stored part signatures. The stored part signatures each include a shape metric that corresponds to geometric attributes of the corresponding 3D model. Methods include receiving input from a user relating to an input part, determining an input part signature that includes a shape metric that corresponds to geometric attributes of the input part, searching the machining knowledge database for similar 3D models based at least in part on the input part signature, and providing the search result to the user. Methods may include associating the input in the machining knowledge database and/or utilizing the search result, for example visualizing a comparison of the input and the search result.