Right now it is used to spawn hidden objects by putting their "name" in the "ifused" field in question.
The most common usage being to place a bunch of soldiers and set them to "spawn at start = no" and then put the name of said soldiers in the ifused field of a trigger zone to make them appear when the player enters that zone (they must all be named the same)
life\'s one big game
windows vista ultimate
i5 @3.3ghz, 4gb ram, AMD R9 200 series , directx 11