SFM
You may have noticed that in The Eternal Truth, there are some very high-quality renders of Foxhole-related shenanigans - this is especially so in most of the front covers. These are created by Souperior, with Valve's free animation software Source Filmmaker. For more information, check our behind the scenes page that goes into depth as to how it works.
All you need to know for now is that a lot of time and effort is put into making everything look good - from single screenshots of one person to entire animations.