Depending on the 3D printer adjustment ratio, Stl files do not need to be processed, just slice them directly. I made the mold parting for a PLA printer(FDM)(render in blue). The Northrop Tacit Blue was a technology demonstrator aircraft created to demonstrate that a low-observable stealth surveillance aircraft with a low-probability-of-intercept radar (LPIR) and other sensors could operate close to the forward line of battle with a high degree of survivability.