glTF to 3MF Converter
FileFlip converts glTF to 3MF entirely inside your browser, using Assimp compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a glTF file to 3MF?#
- Drop your glTF file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to 3MF and the conversion starts on its own. FileFlip downloads 11.2 MB of WebAssembly the first time and nothing after that, then runs Assimp on your own machine.
- Save the 3MF file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting glTF to 3MF lose quality?#
Not in the sense of pixels or samples. Converting glTF to 3MF rebuilds the file in 3MF's own model rather than re-encoding it, so everything 3MF can represent comes through exactly and anything it cannot has to be dropped. Expect the geometry to be exact, and anything the target has no place for, such as a rig, to be left behind.
Is it safe to convert glTF files online?#
Yes, because nothing is uploaded. FileFlip converts glTF files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What glTF to 3MF actually does to the file#
Converting glTF to 3MF runs on Assimp, downloads 11.2 MB of WebAssembly the first time and nothing after that, rebuilds the file in the target's own model, and drops skeleton and animation.
| Engine | Assimp |
|---|---|
| Conversion path | One step: glTF → 3MF |
| Downloaded to your browser | 11.2 MB, once, then cached by your browser |
| Quality | Rebuilt in the target's model |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Materials | Sometimes | Survives for some files and not others. |
| Textures | Sometimes | Survives for some files and not others. |
| Skeleton and animation | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- if the source carries a skeleton or animation, this target has no place to store it
What is a glTF file?#
A glTF file is a JSON scene description, developed by the Khronos Group and first released in 2015, that lists a model's meshes, PBR materials, animations and scene hierarchy while its binary geometry and textures sit alongside it in separate buffer and image files.
Use glTF's JSON form when a pipeline needs to inspect or hand-edit the scene structure directly, since it's plain, indexed JSON.
Convert glTF to GLB when the model needs to travel or load as a single file instead of a folder of JSON, buffers and textures.
What is a 3MF file?#
A 3MF file is a ZIP archive of XML documents, published by the 3MF Consortium in 2015 as 3D printing's replacement for STL, adding the colour, material, unit and multi-object placement data STL never had.
Use 3MF over STL whenever colour, material or multiple positioned objects need to travel with the geometry to the printer.
Convert 3MF to STL only when the destination software is old enough to not support 3MF at all.
glTF to 3MF questions people ask#
What's the difference between glTF and GLB?
glTF is a JSON text file that references its geometry buffers and textures as separate files, while GLB packs that same JSON, the buffers and the textures into a single binary file. Both describe the identical data model; GLB just bundles everything one file needs to travel as one upload.
Why does my glTF file come with extra .bin and image files?
A .gltf file is only the JSON description of a scene, meshes, materials and animations; the actual vertex data lives in one or more .bin buffer files and textures are separate image files that the JSON references by path. Losing any of those files leaves the model with missing geometry or textures, which is why glTF exports usually come as a folder or ZIP rather than a single file.
Is glTF free to use?
Yes, glTF is a royalty-free open standard published by the Khronos Group, with no licensing fee to implement a reader or writer for it. It became an ISO standard (ISO/IEC 12113:2022) in 2022, which is part of why so many engines and viewers support it.
Can glTF store animation?
Yes, glTF's core specification includes keyframed animation and skeletal skinning alongside meshes and materials, which is part of why it replaced COLLADA as the standard for delivering animated 3D content over the web.