Free online X to FBX converter

A legacy DirectX model may need conversion when a current 3D editor or game engine accepts .fbx but not .x. Converting it makes the asset easier to edit, share, and import into applications such as Blender, Maya, Unity, or Unreal Engine.

What the X format is

.x is Microsoft DirectX's legacy 3D asset format, used by older Windows games, DirectX SDK samples, and game-development tools. It can store mesh geometry, materials, texture references, frame hierarchies, bones, skin weights, and animation keys.

X files can be text or binary. They normally contain exported model or scene data rather than an application's complete project, and external textures may be referenced by relative path. Conversion therefore works best when the source file and its texture directory are kept together.

What the FBX format is

.fbx is Autodesk's 3D scene-exchange format. It can contain meshes, transforms, cameras, lights, material assignments, texture links, skeletal rigs, skin weights, and animation, making it suitable for moving assets between applications such as Maya, 3ds Max, MotionBuilder, Blender, Unity, and Unreal Engine.

FBX generally provides broader support for scene hierarchy, rigging, and animation than the legacy X format. Use binary FBX unless a particular pipeline requires the ASCII variant. FBX importer behavior differs between applications and FBX versions, so a file that opens correctly in one program may require adjustments in another.

How to convert X to FBX

Using 101convert.com: Convert the file without installing desktop software by uploading the .x file, choosing FBX as the output format, starting the conversion, and downloading the result. Keep the original file and open the downloaded FBX in a 3D editor to check the result.

Using Assimp: The Open Asset Import Library (Assimp) can import X files and export FBX files when the installed build includes both format handlers.

1. Install the desktop Assimp package for your operating system.
2. Place the X file and its referenced textures in a working folder. Preserve relative paths and avoid renaming resources during conversion.
3. Run assimp export model.x model.fbx -f fbx, replacing the filenames as necessary. Quote paths containing spaces.
4. Open model.fbx in Blender, Maya, or another FBX-capable application and inspect the geometry, materials, skeleton, and animation.

For a visual desktop workflow, use an X-capable importer to open the source, then choose File → Export → FBX. Current Blender installations do not generally include native DirectX X import, so Blender alone is not a dependable first step; use Assimp or another X-compatible importer before using Blender's FBX exporter.

Quality and compatibility limits

• Conversion cannot restore information absent from the X file. Missing textures, unsupported shaders, procedural materials, and externally stored animation may be lost.
• Copy referenced texture folders with the source and relink missing images after import. X texture paths may be relative, absolute, or dependent on the original application's working directory.
• Check vertex winding, normals, smoothing, UV coordinates, coordinate axes, unit scale, and object transforms. Importers may change handedness or apply rotation and scale corrections.
• For skinned models, verify the bind pose, bone names, hierarchy, weight assignments, animation frame rate, and playback. Legacy skeletal animation is often less reliable than static mesh and UV data during conversion.
• Review materials in the destination application. An X shader or DirectX-specific effect usually cannot be reproduced exactly as an FBX material, so assignments may require rebuilding.