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Posts posted by royalwin

  1. 1 hour ago, MatthewS said:

    Runways are long...

    If you have a runway that's 2000m long and a 100m elevation mesh resolution then that's 20 elevation data points along the length of the runway.

    Also "merge in" data points from chart data (eg runway thresholds) and give these higher priority than the elevation mesh.

    The runway can be rendered at a high resolution in game (1cm?) with those 100+ data points being "smoothed" (think bezier curve).

    The result is a smoothly rendered, undulating runway based on the underlying mesh and published data.

    This approach can be applied to the entire airport surface (runways, taxiways, aprons etc)... I guess you need to exclude "spikes" in the elevation data from hangers/terminals etc

    You assume the data is perfect, and even correct.  There just isn't reliable data that represents the actual runway and can have this approach work.  I know it sounds reasonable, but I suggest you try it, and have it work for the whole world.  Unfortunately It won't even though it would be awesome if it did.  The subtle runway imperfections are well below the noise floor of the DEM data.  No signal.

  2. I guess it's not exactly the right place for this post, but since so much discussion has been around it here maybe it's ok.  I thought it might be worth talking a look at the complexity of the problem of "undulating" runways.  I believe some people look at it as if it were a relatively trivial thing to implement and that not doing so somehow shows ignorance, incompetence, or spite on the behalf of the developer.  Not only is that view rather... uncharitable... I think it shows a poor understanding of the magnitude of this problem.  Let's think about it.  First, there are some constraints.  If they are going to make 37,000 airports they need to all work, as in a plane in the sim can land on them, and most planes are not offroad vehicles, so they need to be flat and smooth enough for that purpose.  And they have to be so despite the wildly varying "quality" of the underlying data.  Additionally, this has to be done as procedurally as possible.  Even if you only averaged 2 days per airport you'd be talking about nearly 300 man years of labor, that's just out of control from a cost and time perspective.  So with those constraints, now we have the technical problem.  As a few people here have correctly pointed out, DEM resolution, or the spatial sampling frequency or density or whatever you want to call it is much less than what would be required to capture runway undulations.  30M is pretty high res these days, though there is spot coverage that's better, but much of the world may be 100M or worse.  This will all get better over time, but this is still way short of what's necessary to capture these imperfections as some sort of ground truth.  I wouldn't be surprised if many - most even - of the runways don't even have a single DEM vertex on the actual runway surface.  The belief that you can just drape the textures over the DEM and have usable runways is based on a misunderstanding of the precision of that data.  Not only, that but the problem gets much worse, because the accuracy of the elevation data isn't precise to the level one might suppose.  Airport data has touch down zone elevation and airport elevation, usually to the foot, which is more accurate than the DEM data.  However, it's critical to get the runway data correct, so you have to merge two conflicting data sets, at very different resolution and accuracy and have the airports be correct with no or minimal artifacts.  That's not easy, and on top of that you have photoscenery textures that aren't exactly georeferenced to the airport data so they don't even line up perfectly which can create very unsightly double airport effects.  So you are merging three conflicting data sets.  Tough problem.  Even if you wanted to put these undulations in and have them perfectly match reality, where would you get the data?  Undulations are mistakes.  They are the errors that occurred because the engineers tried to get perfectly flat runways and were unable, or things settled over time.  I'm not aware of a comprehensive data base of survey points along all the runways in the world.  If someone is, please correct me.  The fact that they manually edited, to some extent, 37,000 airports indicates that they couldn't solve all of these issues procedurally.  It's a certainty that the decision to manually do this wasn't taken lightly or even happily, what a massive undertaking!  That they have done so is pretty awesome, and hopefully thinking about it this way will make it easier to appreciate what they've done, rather than conclude that this sim is unusable without these RL undulations perfectly matching reality.  My two cents.

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  3. As JB3DG mentioned above, modern military A/C can exceed M1.0 at sea level.  I'm pretty sure that  F-111 drivers have seen >900 KIAS low level.  Crazy fast!  

    I am not aware of any civilian A/C that could fly that fast down low.  Nonetheless, the point I meant to make was that this sim should be much less stressed by 20 NM/min at high altitude than by 7 NM/min at low altitude, just as far as worst case analysis.

  4. FWIW in my limited (<10 flights) experience in hot air balloons, what I was most struck by was the complete lack of wind and wind sounds.  I guess it makes sense if you think that you are usually moving exactly with the wind so there is no relative wind.  So silent and serene, until the flames shoot up 🙂. Maybe it’s different in more gusty conditions, but those might not be good for balloon flying (shrug)?

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  5. To me, VR is interesting.  I use it in DCS, and I would never go back.  Even the not so great resolution of the original Rift is still a game changer, but I think it's because of the combat aspect.  I'm not sure, even as rabid as I am about how awesome VR is, if I'd want it for an 8-hour airline flight... too uncomfortable and doesn't add enough for me personally.  But VFR?  Pattern work?  Bush plane - VR all the way!  I think the HP reverb resolution is amazing, and I don't personally care about the controllers because I only use VR for simulator games, i.e. seated VR.   I have no interest in room scale VR and I don't use controllers much at all, preferring mouse interaction.  I'm 50+ so that's some more data too.

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