> > Message: 13 > Date: Sat, 30 Jun 2007 22:21:07 +0000 (UTC) > From: Martin Spott <[EMAIL PROTECTED]> > Subject: Re: [Flightgear-devel] Patch for auto-apation of scenery > object > To: flightgear-devel@lists.sourceforge.net > Message-ID: <[EMAIL PROTECTED]> > > Hi Sebastian, > > Sebastian Bechtold wrote: > > >> > As a very first attempt to contribute to the flightgear source code, I >> > have tried to write a patch that automatically sets a scenery model's >> > elevation to ground level at the object's site if an elevation < 9999 is >> > defined in the .stg file. >> > > For some cases this is certainly a good idea. The Berlin Scenery for > example that we used for LinuxTag2007 has places where the elevation > differs from the standard Scenery - simply because this special Scenery > was created from more detailed data. > This difference results in some VOR and ILS antennas floating above the > ground - which looks a bit strange when you have to 'hop' over the > localizer at EDDI 27L before touchdown and which could be cured by your > approach :-) > > BUT, I'm sorry to say it, finally this doesn't work out for many, > _many_ (actually: most) Scenery objects because many 'generic' objects > are sunk into the ground intentionally. > > The obstruction databases that are being used to place generic objects > into the scene define lots of scyscrapers and towers at different > heights. In order to avoid creating one generic object for every > possible height (note, we have more than 180k Scenery objects !) we use > just a couple of different generics which are then being sunk into the > ground to show up in the Scenery at correct height. In the Scenery > Objects Database the respective difference between the height of the > generic model and the height in real life (in the Scenery) is being > stored as an "elevation offset" > > Now, don't discard your patches .... Probably one day we have a > modified scenery format that allows us to carry this elevation offset. > > Cheers, > Martin.
Hi Martin, and thanks for your reply. Unfortunately, I am unable to read from your posting what the problem is. Of course I know that the possibility to define an explicit elevation value for an object is required for the things you described. I don't want abandon it, I just want to add the possibility to set it to some special value that is recognized by the program as "place this at ground level". If you think -9999 isn't a good value, what about -10000000 or, say, 23804234,234 ? As far as I understand this thing, the only criterion is that it's an elevation which is probably never explicitly stated for an object which does -not- sit on ground level. The idea was that I want to provide a way to place scenery objects on ground level without having to know the scenery terrain elevation at this point. This would greatly simplify the creation of sceneries without having to use the UFO. I's easy to find out "believable" lat/lon coordinates for an object, since nobody notices a few meters of abberation, but it's practically impossible to find out the ground elevation in the scenery without starting flightgear (or some other tool capable of reading and displaying terragear terrain data). I didn't even think about the possibility to use the same object placement files with different terrain scenery files, but you are perfectly right that this is another situation where this feature would be very useful. I can understand and accpect if my idea and/or implementation wasn't the best. Actually, that's what I expected, but I expected something like "don't do this there and in this way, a concept (...) in class/method (...) is the better way to go". So what's the point now? With best regards, Sebastian ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
