Maya is used for a lot of 3D modeling. Modelers frequently save their completed work in a FBX file. FBX is a proprietary format designed by Autodesk (check this). In addition to the model, it contains the textures, rigging, and animation. It is a very convieient format, if you have an appropriate library of other tool to unpack it. Blender is an open-source modeling program. There is an FBX importer in Blender that handles many of the features and variations of the FBX format.