Re: [Flightgear-devel] Helipad thresholds

[James T. <ja...@fl...>]

> On 23 Jun 2023, at 00:08, David Megginson <dav...@gm...> wrote:
> 
> The threshold.xml file tells FlightGear where to start the aircraft (on runway); otherwise, is was placing them in incorrect positions for updated airports.

This is not quite my understanding. What I understood is that the threshold.xml overlays (replaces) the base apt.dat data for the runway threshold. So yes you can use it to ‘fix’ where the threshold is, if it’s not correct (or no longer correct) in the apt.data definition. But for helipads we always use the centre of the pad.

Since we now support apt.dat overlays in scenery, I would have guessed for helipads you would be better to supply correct data in your dave_scenery_apt.dat, rather than supply thrshold.xml files at all.

However, I’ve never built custom scenery, only worked on the loading / processing of this stuff at runtime in FG, so maybe I have something incorrect here?

> 
> Note also that — I think — some runways for fixed-wing aircraft have only one threshold as well.

Yes, but this is not supported in FG right now (there’s a few places with a ‘TODO : support single ended runways’ in the code)

Kind regards,
James