That's the point Curt. I don't care about that now. That's not my aim in
any way. Your "algorithmic" approach suits well when thinking globally,
and you have to, because you provide a base to a global scenery
generation process; that has to follow strict, standardized rules.
All that is good but this thread is not about a new way to get the
global scenery regenerated with more details, it's about customizing
(with high level of freedom) just a few airports, juts the ones a few
people are especially interested into.
Right, we are talking about the same thing here.
I see space for doing that, it's just about modelling geometry of
restricted world areas and integrating it with the already existing
terrain mesh; but tools around do not provide a way to develop it (I
mean taxidraw/fgsd, maybe even Terragear tools).
I don't know if I was successful, but when discussing the upcoming apt.dat format to include a much more flexible taxiway spec, I also lobbied to have an airport boundary also included. If this boundary was fixed and never changed, then a user could change anything inside that boundary (leaving the actual boundary points intact) and their airport would always mesh in perfectly with the surrounding terrain, even if we autogenerated the world again.
Right now the airport boundaries are derived from the runway/taxiway data so if those change in the slightest bit, the terrain cutout for the airport also needs to change ... that's a hard problem to deal with.
So back to your point, there's no reason you couldn't convert an airport model to a more convenient 3d model format and then edit it in what ever tool you want ... ac3d, multigen creator, blender, etc.