How do you add custom buildings to FSX? I have G-max and know pretty much how to create buildings and all, but not sure how to add them to FSX. See, I work at International Jets here at Gadsden Regional KGAD in Alabama. There is a building on the airport in FSX that is in the right place but I thought it would be cool if I could somehow replace that building with a G-max model of the correct size and shape. Maybe even add a few static L-39s sitting outside. Then all the guys that have Lotus' fine L-39 can take them there to get serviced LOL.