FBX explained: what it is, and why browsers only read it
FBX is Autodesk's proprietary interchange format — ubiquitous in DCC pipelines, awkward on the web. What an FBX holds, why importing works but exporting from a browser doesn't.
What FBX carries
Filmbox/FBX is Autodesk's proprietary binary format: meshes, skeletons, skin weights, animation takes, cameras, lights, and material references. Its strength is pipeline depth — a character rig with 200 animation clips travels in one file. Its weakness is licensing: the full spec is not open, so implementations vary in what they support.
Why browsers can read FBX but not write it
Open-source parsers exist for importing FBX into WebGL scenes — they extract geometry, materials and the animation tracks browsers can actually play. Writing a spec-complete FBX (rigs, takes, binary 7.x headers) requires the proprietary SDK, which is why honest web tools import FBX and export glTF instead.
The FBX viewer on this site does exactly the import side: drop an FBX, see the meshes and animation, then decide what to do with it.
The practical pipeline
FBX in from the DCC tool → view or inspect in the browser → export GLB for web delivery, since GLB carries PBR materials and animations in an open spec. If the FBX holds rig and clips you need, keep the FBX in the pipeline and treat GLB as the web-facing copy.