Open STL files and other 3D files (OBJ, 3MF, GLB, STEP, USDZ and more) and see them: most open in about two seconds. 3D Viewer shows the models you print, download or export, with no account, no sign-in and nothing to set up. STL thumbnails and the preview pane in File Explorer: with the optional Pro add-on, File Explorer itself shows your STL, 3MF, OBJ and STEP models, as thumbnails and in the preview pane (Alt+P). It reads STL (binary and text), OBJ, PLY, 3MF, FBX, glTF/GLB (including Draco, KTX2 and meshopt compressed files) and STEP (.step, .stp), and also opens IGES (.igs, .iges). 3MF, FBX and STEP models are scaled by the unit stored in the file, so a part shows at its real size in millimetres. Large STEP files can take up to a minute to open. For SketchUp (.skp) files it shows the preview picture SketchUp saved in the file, with the file's details; it can't open SketchUp models in 3D. It also opens USDZ files (and .usd, .usdc and .usda), such as Apple's AR Quick Look models and 3D scans; Pro saves them as STL, 3MF, OBJ or GLB. 3D Viewer Pro is an optional add-on, bought once through the Microsoft Store. It shows your models as small 3D pictures in File Explorer: STL, OBJ, 3MF, GLB, glTF, PLY and STEP (.step, .stp) files, and SketchUp (.skp) files show the preview picture SketchUp saved in them. If another Store app, such as Microsoft 3D Viewer, opens a file type, make this app the default for that type to see the pictures. It also finds and repairs holes and flipped faces (and tells you when a model is too damaged to repair safely), scales a model to an exact size in millimetres or per cent, and saves it as STL, 3MF, OBJ or GLB. STEP parts can be saved as STL too. STEP files over 32 MB, .gltf files that keep their data in a separate .bin file, and files that take too long to read, show a plain picture instead. Viewing stays free. Microsoft removed its 3D Viewer app from the Store in July 2026. This viewer opens the same kinds of files, including the .3mf and .glb files that 3D Builder and Paint 3D saved. For people who used 3D Builder to fix files before printing: Pro repairs holes and flipped faces, scales a model to an exact size and saves it as STL or 3MF. Northgable is not affiliated with Microsoft. SketchUp is a trademark of Trimble Inc.; FBX of Autodesk, Inc.; glTF of the Khronos Group; Apple of Apple Inc.
Photo & Video · Windows · Free
