The Direct3D file format stores meshes, textures, animation sets, and user-definable objects, facilitating the exchange of 3D information between applications. Support for animation sets allows predefined paths to be stored for playback in real time. Instancing and hierarchies are also supported, allowing multiple references to a single data object (such as a mesh) while storing the data for the object only once per file.
Direct3D files have a .x file name extension. This DirectX Software Development Kit (SDK) includes conversion tools (Conv3ds.exe and Convxof.exe) that allow you to convert files from .3ds files generated by Autodesk 3D Studio and from .xof files that were generated for earlier versions of Direct3D.
The Direct3D file format is used natively by the Direct3D Retained-Mode API, providing support for loading predefined objects into an application and for writing mesh information constructed by the application in real time.