After making a master mission, I notice that when DCG "generates" the campaign files it removes quite a few objects that I specifically populated the map with to "pretty it up". Is this an object number limitation or is it something to do with supply? Stationary ships, stationary vehicles and stationary planes seem to be the main items removed, which makes me think they have to have a matching non stationary type in the master mission to prevent them being removed? Though that said sometimes static "objects" are removed

 

Static objects are either "red", "blue" and they'll spawn depending on which controls the location.  Make sure you give all units the proper allegiance. 

 

Planes are special.  They have their own rules.  Planes must be either red or blue.  The game will then spawn them only if their side controls the airfield.  And then, they will only spawn them if there is a squadron located at the airfield.  Finally, it will spawn a plane that matches one of the squadrons located at that field.

 

They will not spawn if you have a non-airfield location closer to the spawn coordinates than the airfield location.

 

Ships are also a bit special.  They spawn based on who controls the nearest water location.  Only "_Harbor" locations (and a few others) can be permanently controlled by a side.  Things like "_Oceans" and "_Seas" are only controlled so long as a friendly non-static ship is present.