The Source Filmmaker (SFM) is the movie-making tool built and used by us here at Valve to make movies inside the Source game engine. Because the SFM uses the same assets as the game, anything that exists in the game can be used in the movie, and vice versa.
Source Filmmaker (SFM) is a free 3D computer graphics software tool published by Valve for creating animated films, which uses the Source game engine. [6] Source Filmmaker has been used to create many community-based animated shorts for various Source games, such as Team Fortress 2, the Left 4 Dead series, and Half-Life 2.
Source Filmmaker is a powerful engine tool, running on the Alien Swarm engine branch of Source to create a flexible, modifiable 3D recording that can be exported as a movie or as a still image.