SCS Software creates a wide range of Truck simulation games. They're currently working on "SCS Blender Tools", an add-on to create buildings and custom models for their games.
SCS Software writes:
SCS Blender Tools we are building are going to be 100% "developer grade". The package will be using exactly the same approaches and workflows we use for creating our games, in fact some people on SCS team plan to start using them on a daily basis, replacing current tool pipeline. With SCS Blender Tools, it will be possible to comfortably create models, texture them, assign and tweak correct materials, and export everything to the engine.
The plan is that with SCS Blender Tools it will cover everything - from the simplest models of buildings to fully fledged trucks, just as us developers are doing it. With provided documentation we hope to see even higher quality creations from our modding community. With community-created assets in source form compatible with SCS Software's internal processes, and with the map editor a native part of the game itself, this may open up huge opportunities for the future.