twineconvert

free · in-browser · no upload

FBX to STL
Converter

Drop your FBX file. We'll convert it to STL right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .fbx

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a FBX from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your STL the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Formats involved

About FBX and STL

FBX, Autodesk Filmbox

FBX is Autodesk's proprietary 3D interchange format, originally built for Kaydara's FilmBox motion-capture tool (hence the name) and acquired by Autodesk in 2006. It carries meshes, materials, rigs, skeletal animation, blend shapes, cameras, and lights in one file, which made it the de facto asset format for game engines: Unreal Engine, Unity, and Epic's Fab marketplace all ingest FBX as a first-class citizen. Two encodings exist, binary (common) and ASCII, both versioned; modern tools write FBX 7.x.

How to open

Unreal Engine and Unity import FBX directly. Blender opens it via File > Import > FBX. Autodesk's free FBX Review (Windows/macOS) previews files without a full DCC install. Maya, 3ds Max, Cinema 4D, and Houdini all read and write it natively.

Full FBX format guide →
STL, Stereolithography

STL is the lingua franca of 3D printing, every slicer (PrusaSlicer, Bambu Studio, Cura, Simplify3D) reads it. Files are unstructured triangle soup: no scene graph, no materials, no scale info, just vertices and triangles. The format is ancient (1987) and primitive but its simplicity is exactly why it's universal. Two variants: ASCII (human-readable, big) and binary (compact, what most software produces).

How to open

Every 3D printing slicer, every CAD/3D tool (Blender, FreeCAD, Fusion 360, SolidWorks, Tinkercad). Free viewers: ViewSTL, MeshLab, online STL viewers.

Full STL format guide →

Related tools

Convert other files to STL

Convert your FBX to other formats

FAQ

Common questions

Is this FBX → STL converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert FBX to STL?

Shipping rigged, animated 3D assets into game engines and between DCC tools. 3D printing, feed an STL into your slicer to get G-code. The most common reason to convert is compatibility, STL works in places where FBX doesn't, or vice versa.

How do I open a FBX file in the first place?

Unreal Engine and Unity import FBX directly. Blender opens it via File > Import > FBX. Autodesk's free FBX Review (Windows/macOS) previews files without a full DCC install. Maya, 3ds Max, Cinema 4D, and Houdini all read and write it natively.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.