3D Model Converter & Viewer — STL, OBJ, FBX, GLB, glTF, USDZ, 3MF
View and convert STL, OBJ, FBX, GLB, glTF, PLY, 3MF, DAE and USDZ in your browser. Batch convert to GLB, OBJ, STL, USDZ or 3MF.
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This free 3D model converter opens STL, OBJ, FBX, GLB, glTF, PLY, 3MF, Collada (DAE), 3DS, USDZ, VRML and OFF files in your browser, shows them in an interactive viewer, and converts them to GLB, glTF, OBJ with MTL, STL, PLY, USDZ or 3MF. Drop one file or twenty, or a ZIP that contains the model with its textures, and download each result or the whole batch as a ZIP. It doubles as a quick GLB viewer and STL viewer: drag to orbit, check the dimensions and triangle count, look at the wireframe and normals, play the animations.
Everything runs locally with three.js, so a confidential CAD part or an unreleased game asset never leaves your machine, and there is no upload queue. The tool is upfront about what each conversion keeps: STL and PLY have no materials, 3MF keeps one colour per object, OBJ has no animation, and FBX is a proprietary format that browsers can read on a best-effort basis but cannot write at all, so FBX is offered as an input only.
How to use
- Drop your 3D files onto the box, or click to choose them. Include the .mtl and textures with an OBJ, and the .bin and textures with a .gltf, or zip the folder and drop the ZIP.
- Click a file in the list to view it. Check the model info and warnings, and fix the orientation or source units if the model is lying down or the wrong size.
- Choose the output format under "Convert to" and, if needed, the output units, up axis and placement.
- Press Convert. Each file shows its output name, size and any notes about what the format could not keep.
- Download files one by one, or press "Download all (.zip)" for the whole batch.
Frequently asked questions
How do I convert STL to OBJ (or OBJ to GLB)?
Drop the file onto this page, choose the target format under "Convert to" and press Convert, then Download. STL to OBJ keeps the geometry exactly; OBJ to GLB keeps geometry, UVs, materials and textures as long as you drop the .mtl and texture images together with the .obj (or zip them). Dedicated pages such as STL to OBJ and OBJ to GLB do the same with the target preselected.
Can I convert FBX to GLB, and can I convert to FBX?
FBX to GLB works for most files: meshes, skinned characters and animations usually come across, while complex materials and some embedded textures may not. Converting to FBX is not possible in a browser, because FBX is a closed format with no open-source writer; use Blender (free) or Autodesk's FBX Converter for that. This tool never offers an FBX output it cannot produce properly.
Which conversions lose information?
STL keeps triangles only, so colours, materials, UVs and animation are dropped. PLY keeps vertex colours, normals and UVs but no materials. 3MF keeps one display colour per object. OBJ keeps geometry, UVs and basic materials but no animation or skinning. GLB, glTF and USDZ keep the most, including PBR materials, textures and animation. The tool states the loss for your chosen target before you convert.
Why is my converted model the wrong size or lying on its back?
STL, OBJ and PLY store no units, and some formats are Z-up while glTF is Y-up. Set "Source units" to what the numbers mean (STL is usually millimetres, glTF is always metres, FBX is often centimetres), and tick "Model is Z-up" if it lies on its back. On "Auto", printing formats are written in millimetres and Z-up, and conversions between unitless formats keep the numbers unchanged.
Is there a file size limit, and are my files uploaded?
Files are not uploaded: they are read and converted by your browser, which is why the limit is your device's memory. The tool accepts up to 20 models per batch and 250 MB per file; very large FBX or glTF scenes may need a desktop browser with plenty of RAM.
Can I view GLB, STL or USDZ files without converting them?
Yes. Drop the file and it opens in the viewer with orbit, pan and zoom, wireframe, normals and bounding-box overlays, lighting presets, a transparent background option and animation playback. The info panel lists meshes, materials, textures, animations, triangle and vertex counts and the model's dimensions, and you can download a PNG of the view.
Supported formats and what survives
• Inputs: STL (binary and ASCII), OBJ with MTL and textures, GLB, glTF with .bin and textures (Draco and Meshopt compression supported), PLY (meshes; point clouds view only), 3MF, FBX (binary and ASCII), Collada DAE, 3DS, USDZ/USDA/USDC, VRML (.wrl) and OFF.
• Outputs: GLB, glTF (.gltf + .bin, or embedded), OBJ + MTL (+ textures), STL (binary or ASCII), PLY (binary or ASCII), USDZ and 3MF.
• Full fidelity: GLB ↔ glTF, and most things into GLB. Partial: FBX, Collada and USD materials, which are approximated as PBR materials. Geometry only: STL. Not possible here: writing FBX, STEP or other CAD formats, and decoding KTX2/Basis textures.
Units and orientation, explained
Most "my model is tiny" or "my model is huge" problems come from units. glTF and USDZ are defined in metres. STL, OBJ and PLY have no units at all, and the convention depends on the tool that wrote them: slicers and CAD exports assume millimetres, Blender's OBJ export uses metres. The converter shows the size it thinks the model is; if that is wrong by a factor of 10, 100 or 1000, change "Source units" and convert again.
Orientation follows the same pattern. glTF and USDZ are Y-up by definition, printing formats and most CAD tools are Z-up. On Auto the converter writes STL, PLY and 3MF Z-up and everything else Y-up, so a model converted from GLB to STL stands upright on the build plate.
Batch conversion
Drop up to 20 models at once (or a ZIP of a folder). They load one after another, each with its own status, and "Convert all" turns every loaded model into the chosen format. A file that fails shows the reason and does not stop the rest. Multi-file outputs, such as OBJ with its MTL and textures or glTF with its .bin, are kept together in a folder per model inside the batch ZIP.
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