STL Viewer helps makers inspect a 3D model before sending it to a slicer. It opens STL, 3MF, OBJ, PLY, OFF, 3DS, GLB, and glTF files, displays dimensions and mesh details, and can measure distances between model points. A print estimate uses selected printer and material settings to approximate weight, filament, time, and cost. Models can be placed in AR at real scale, viewed in a section cut, or exported as STL. The app works offline and the developer says models stay on the device. It is free, with no account or in-app purchase; Apple labels the app as containing advertising, while the developer describes at most a small banner. It does not edit, repair, slice, or print models, and some CAD formats must be exported first.
