.DMX File Extension
What is a DMX file?
A DMX file is an animation project created by Source Filmmaker (SFM), a tool that allows users to create animated movies using Valve Source engine game assets. It contains an editable movie set within a Team Fortress 2 map. DMX files also contain other Team Fortress 2 game objects, such as characters and items, as well as animations, sounds, and visual effects. The files may also contain recorded Team Fortress 2 gameplay.
SFM is a free program that Team Fortress 2 enthusiasts can use to create animated movies and still images starring the game's characters. To do so, users first import a Team Fortress 2 map, which serves as the setting for their movie. The user can then import and animate Team Fortress 2 characters and items, add sounds to their movie, and add visual effects to their movie.
When a user saves an in-progress SFM movie project, the project is saved as a DMX file. DMX files are comprised of a sequence of shots, which are themselves comprised of the elements mentioned above. Each DMX file's shot sequence appears as an editable timeline in SFM.
NOTE: You may see DMX files referred to as sessions in SFM's documentation. A DMX file and SFM session are the same thing.
How to open a DMX file
You can open an SFM file in Source Filmmaker (Windows). To do so, select File → Open... from the program's menu bar. Then, navigate to and open your SFM file.