Elevation Correction with x-plane?

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criley
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Elevation Correction with x-plane?

Postby criley » Thu Dec 06, 2018 12:36 am

I have been flying with P3D and FSX players and their elevation tends to be 30-50' off from where I am. I have tried to check and uncheck the box in settings as well as checking and unchecking "Runways follow Terrain" in x-plane to no avail. Has this ever worked between these sims? If so, is there a trick?

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Peter
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Re: Elevation Correction with x-plane?

Postby Peter » Thu Dec 06, 2018 10:34 am

I don't think that has worked correctly in X-Plane previously. It seems difficult to get the ground elevation beneath the other aircraft. Without that information it's not possible to correct for it. Prepar3D/FSX provides this information for all objects.

I think I can fix it for shared cockpit at least. I'm just looking at that now.

Peter

wing_man
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Re: Elevation Correction with x-plane?

Postby wing_man » Thu Dec 06, 2018 7:45 pm

other services such as PilotEdge use some type of technique called "snap" or "snap-to-grid" (I'm sure Im butchering that name) which is something to keep the airplanes affixed to the runways. Might be worth checking into.

EDIT: I knew I butchered the technique that is used, it is called "Clamping" and perhaps that is their own term for it and not an industry term.

Daikan
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Joined: Sun Dec 16, 2018 11:15 pm

Re: Elevation Correction with x-plane?

Postby Daikan » Tue Dec 18, 2018 5:32 am

Peter wrote:It seems difficult to get the ground elevation beneath the other aircraft. Without that information it's not possible to correct for it. Prepar3D/FSX provides this information for all objects.

You can probe the terrain using the SDK: https://developer.x-plane.com/sdk/XPLMProbeTerrainXYZ/

For example the IVAO client (x-Ivap) uses this for clamping. The source code for correcting aircraft position is available here:
https://sourceforge.net/p/x-ivap/code/H ... r.cpp#l612

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Peter
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Re: Elevation Correction with x-plane?

Postby Peter » Tue Dec 18, 2018 7:25 am

Daikan wrote:You can probe the terrain using the SDK: https://developer.x-plane.com/sdk/XPLMProbeTerrainXYZ


Obviously didn’t look hard enough. That’s perfect, just made the job a lot easier. Thanks.

Peter

skelsey
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Re: Elevation Correction with x-plane?

Postby skelsey » Tue Jan 08, 2019 11:56 pm

Hi Peter,

FYI had an odd experience with elevation correction this evening - I was running FSX-SE with test version .20 and the other pilot was running P3Dv4 with .18

On the ground when the other pilot had the controls there was a lot of jittering on my side and my aircraft was rolling when going round corners on the ground etc (a common problem I have noticed when connecting to others using P3D).

I took the controls and flew the takeoff. All fine until I handed control back to the other pilot at which point my aeroplane immediately "snapped" to the ground - whilst my student was flying quite happily at 3000ft!

I turned off elevation correction in my settings and all was well again. Interestingly when we taxied back in the synchronisation on the ground was much improved on my side with no jittering and the aircraft staying level during turns, so it seems like there was something odd going on with the elevation correction!

The fix from my point of view is obviously to turn it off, but not sure if there was something there you would want to investigate from your point of view!

Cheers,

Simon

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Peter
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Re: Elevation Correction with x-plane?

Postby Peter » Wed Jan 09, 2019 9:35 am

Hi Simon,

As mentioned in the change log, you both need to be on at least 1.4.20 otherwise you'll likely see some odd things happening.

Peter

skelsey
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Joined: Wed Apr 26, 2017 7:51 pm

Re: Elevation Correction with x-plane?

Postby skelsey » Wed Jan 09, 2019 1:57 pm

:oops: guilty, sorry!

Will try with .20 on both sides and report back!


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