X (Direct X File)

The X 3D file format extension was introduced by Microsoft with the launch of Version 2 of their 3D graphics API, Direct X, back in 2002. The format has evolved over the years; however, in 2014, the X file format was deprecated in favor of newer, more capable formats such as FBX.

The format is a simple text-based file capable of storing 3D mesh information such as vertices, faces, normals, and material information. In addition to basic 3D information, the format can also store animations with the X file format, which is primarily used in the development of games.