why is the PHOG airport groundlayout "popup"-radius that small, it's @ ~6 DME?
No, it's not, if you are referring to ground vehicles, their range it's 0.5 NM for each group of objects measured from each center point but, you can control it with the Anti-popup setting in the Addon Manager, which can go up to 30, that's why it default to a small value, so users with low-end system don't experience fps loss, and users with fast systems can just crank the Anti-pop setting and increase all the ranges up to 30x.
However, nothing will be loaded anyway outside the global scenery range, which is 10.0 NM (regardless of high the Anti-popup is), which is the range of the main buildings so, with Anti-popup at 30, everything will be loaded at 10.0NM.
But, as usual, it's not so simple, because some objects like ground vehicles, also have a maximum altitude visibility range, and they also have several complexity levels so, for example, cars in the parking lot appear more and more dense when going close.
