AMF to STL Converter
FileFlip converts AMF to STL 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 an AMF file to STL?#
- Drop your AMF 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 STL 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 STL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting AMF to STL lose quality?#
Not in the sense of pixels or samples. Converting AMF to STL rebuilds the file in STL's own model rather than re-encoding it, so everything STL 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 AMF files online?#
Yes, because nothing is uploaded. FileFlip converts AMF 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 AMF to STL actually does to the file#
Converting AMF to STL 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 materials, textures and skeleton and animation.
| Engine | Assimp |
|---|---|
| Conversion path | One step: AMF → STL |
| 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 | Dropped | The target format has nowhere to put it. |
| Textures | Dropped | The target format has nowhere to put it. |
| Skeleton and animation | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- the target stores triangles and nothing else, so materials, colours, and texture coordinates have nowhere to go
- if the source carries a skeleton or animation, this target has no place to store it
What is an AMF file?#
An AMF file holds a 3D-printable object description in XML, adding curved triangles, per-vertex colour, multiple materials and lattice structures beyond what STL's flat triangle mesh can record.
Use AMF when a tool specifically outputs it and needs to carry colour or multi-material data that STL can't hold.
Convert AMF to 3MF or STL for any modern slicer, since that's what current 3D printing software actually expects.
What is an STL file?#
An STL file is a triangle mesh created by 3D Systems in 1987 for its stereolithography 3D printers, storing nothing but a flat list of triangle facets and their normals, with no colour, material or unit of measurement attached.
Use STL when the only destination is a 3D printer's slicer, which is all the format was designed to feed.
Convert STL to 3MF when colour, material or unit information needs to travel with the geometry, since STL has nowhere to put any of it.
AMF to STL questions people ask#
What is an AMF file used for?
AMF is a 3D printing format meant to describe an object's colour, materials and curved surfaces alongside its geometry, which is more than STL, the format it was designed to replace, can store.
Is AMF better than STL?
AMF stores more than STL, including colour, multiple materials, curved triangles and units, all things a bare STL file has no field for. That richer feature set never translated into wide slicer support, so most workflows still default to STL or 3MF.
Why did 3MF replace AMF?
3MF launched in 2015 with backing from major CAD and printer vendors and a simpler, ZIP-based structure, and it picked up the slicer and printer support that AMF, despite arriving first with similar goals, never got.
What is an STL file used for?
An STL file is the standard input for 3D printer slicing software, storing a model's surface as a list of triangles with nothing else attached. Slicers use it to work out where to lay down material layer by layer.