PLY, polygon file format, represents 3D file format that stores graphical objects described as a collection of polygons. The purpose of this file format was to establish a simple and easy file type that is general enough to be useful for a wide range of models. PLY file format comes as ASCII as well as binary format for compact storage and for rapid saving and loading.
FBX, FilmBox, is a popular 3D file format that was originally developed by Kaydara for MotionBuilder. It was acquired by Autodesk Inc in 2006 and is now one of the main 3D exchange formats as used by many 3D tools. FBX is available in both binary and ASCII file format. The format was established to provided interoperability between digital content creation applications.