Convert FBX to OBJ

Why convert FBX to OBJ?

FBX to OBJ is a common step when you need a simpler, more widely readable file. OBJ opens in nearly every 3D program, needs no SDK and is easy to inspect, while FBX is a heavier format tied to a vendor's toolkit. Typical reasons are importing an asset into a program that lacks FBX support, handing a model to a client, or stripping a scene down to its meshes. The geometry, normals and UV coordinates carry across, and materials are written to an MTL file. What OBJ cannot hold is the rest of what FBX does well: skeletons, animations, cameras, lights and the full scene hierarchy. Meshes keep their object names where possible.

How to convert FBX to OBJ

1. Drop your FBX file (with its textures, if separate) onto the converter — it opens in your browser, nothing is uploaded.
2. Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
3. Choose OBJ as the output and click Convert. Several files download as one ZIP.

What carries over from FBX to OBJ

What changes

• Animations, skeletons and skin weights are removed; only the posed mesh remains.
• Cameras, lights and other scene objects are not exported.
• Basic colours and texture references are kept via an MTL file; advanced shader settings are simplified.
• Centimetre units become the OBJ's numbers as scaled, so check the size in your target program.

Tips

• Keep the texture image files next to the OBJ and MTL, or the textures will not display.
• If you only need the geometry, ignore the MTL and assign your own materials.
• Check that normals and UVs look right in Blender before sending the file on.
• OBJ has no unit field; note the intended scale for whoever receives it.

About FBX files

FBX began as Filmbox, a motion-capture tool from Kaydara, and Autodesk bought it in 2006 and kept developing it as a proprietary format. It has no public specification; the supported way to read or write it is Autodesk's FBX SDK, and other tools rely on that SDK or on reverse-engineered code. There is a binary encoding and an older ASCII one. FBX is more than a mesh container: it stores scene hierarchies, materials, cameras, lights, skeletons, skinning weights and animation takes. For that reason it became the usual bridge between modelling and animation packages such as Maya and 3ds Max and game engines such as Unity and Unreal. Scale and axis conventions vary by exporter, with centimetres being the common default, so an FBX can look wrong in a different program until the unit and up-axis settings are checked.

About OBJ files

OBJ comes from Wavefront Technologies' Advanced Visualizer software in the 1980s, and it has outlived the product. A file is plain text: lines starting with v define vertices, vt texture coordinates, vn normals, and f faces that reference those lists by index. Faces may be triangles, quads or larger polygons, and the g and o keywords group faces into named objects. Appearance is not in the OBJ at all; a line called mtllib points to a separate .mtl file that lists materials with diffuse colours and texture image names. The format is verbose, has no official unit and no scene hierarchy or animation, but it is trivial to read and write. That is why scanners, photogrammetry tools, sculpting programs and game pipelines still use it to move static meshes around.

3D printing notes

Slicers do not take FBX, so the file has to be converted to a mesh format first. Animation and rigging are irrelevant to printing, so only the posed geometry matters. Many FBX models are in centimetres, which means a character that is 18 cm tall in the file must end up as 180 mm; reading it as millimetres gives 18 mm, and reading it as metres gives a huge model. MeshShift defaults FBX to centimetres, shows the real dimensions, and lets you change the unit. It reads FBX but does not write it, so a typical path is FBX to STL or 3MF, followed by the print check to close holes between separate body parts.

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