DirectX X to FBX Converter
FileFlip converts DirectX X 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 an DirectX X file to FBX?#
- Drop your DirectX X 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 DirectX X to FBX lose quality?#
Not in the sense of pixels or samples. Converting DirectX X 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 DirectX X files online?#
Yes, because nothing is uploaded. FileFlip converts DirectX X 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 DirectX X to FBX actually does to the file#
Converting DirectX X 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: DirectX X → 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 an DirectX X file?#
An X file is Microsoft's DirectX mesh format, storing geometry, materials, textures, skinning and animation as a set of typed data templates, in either a human-readable text encoding or a tokenised binary one.
Use X only to keep compatibility with older DirectX SDK samples or a legacy pipeline built around the format.
Convert X to FBX or glTF for any current game or graphics pipeline, since DirectX itself has moved on from the format.
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.
DirectX X to FBX questions people ask#
Is the X file format still used?
Rarely for new work. It's tied to Direct3D's Retained Mode API, which Microsoft stopped updating after DirectX 3.0 and later dropped outright, so current DirectX pipelines use FBX or glTF instead.
What is a DirectX X file used for?
An X file stores a 3D mesh for Microsoft's DirectX, including materials, textures, skinning and animation, laid out as a set of typed templates. It was the standard model format across the DirectX SDK samples through the 1990s and 2000s.
Why do some .x files look like source code instead of a 3D model?
The .x extension is shared with Lex lexical-analyzer source files on Unix systems, an unrelated format entirely. A text-encoded DirectX X file is also readable as plain text, but it starts with the header "xof" rather than Lex syntax.
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.