PMX to FBX Converter
FileFlip converts PMX to FBX 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 PMX file to FBX?#
- Drop your PMX 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 FBX 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 FBX file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting PMX to FBX lose quality?#
Not in the sense of pixels or samples. Converting PMX to FBX rebuilds the file in FBX's own model rather than re-encoding it, so everything FBX 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 PMX files online?#
Yes, because nothing is uploaded. FileFlip converts PMX 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 PMX to FBX actually does to the file#
Converting PMX to FBX 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.
| Engine | Assimp |
|---|---|
| Conversion path | One step: PMX → FBX |
| 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 | Sometimes | Survives for some files and not others. |
What is a PMX file?#
A PMX file is a binary character model for MikuMikuDance, the successor to the older PMD format, built by Yu Higuchi's tools to hold a mesh alongside its bones, facial morphs and rigid-body physics as one package that MMD loads and animates directly.
Use PMX when a character needs to be posed, animated or physics-simulated inside MikuMikuDance or the wider MMD tool ecosystem.
Convert PMX to glTF or FBX when an MMD character needs to move into a game engine or renderer outside the MMD ecosystem.
What is an FBX file?#
An FBX file is Autodesk's proprietary binary or ASCII scene format, originally built by Kaydara for its Filmbox motion-capture software in 1996, that carries a full scene, meshes, materials, skeletons, skinning and animation together in one container.
Use FBX when a full rigged, animated scene needs to move between a DCC tool and a game engine, since almost every pipeline tool expects it.
Convert an FBX file when the destination needs an open, patent-unencumbered format, or when the application that wrote it isn't the one reading it and something is coming through wrong.
PMX to FBX questions people ask#
What is a PMX file?
A PMX file is a MikuMikuDance character model, storing a mesh together with its bones, facial morphs and rigid-body physics in one binary file. It's the successor to the older PMD format and the format almost all current MMD character content is distributed in.
What's the difference between PMD and PMX?
PMD is the older MikuMikuDance model format, and PMX succeeded it with a more flexible bone and morph system, support for more materials, and additional physics options. PMX Editor can open and convert PMD files, and current MMD content is essentially all PMX now.
Can I open a PMX file outside MikuMikuDance?
Yes, Blender opens PMX files through the community mmd_tools add-on, which reads the mesh, bones, morphs and physics much the way MikuMikuDance does. Outside of MMD-focused tools, native PMX support is rare.
What software opens FBX files?
Blender, Autodesk Maya, 3ds Max, Unity and Unreal Engine all open FBX files, since it's the format most 3D and game pipelines use to move scenes between tools. Which application wrote the file matters more than which one is opening it, because FBX exporters don't all interpret the format identically.