The GMS file format, conversely to most others, is NOT skeleton-based, and is binary. A closed binary file format developed by House of Moves for use in their proprietary software called (at the time) Diva. This file format is essentially a dump of a Diva scene. It includes all translational marker data as well as all rotational bone data in the scene and more. The FBX proprietary file format (.fbx) owned by Autodesk since 2006. The Blender Foundation has published an unofficial specification for binary FBX.