XSB - FSX/P3D sync of vertical position on ground

[Stephen Odgaard]

Hi,

 

I have been using FS9 and VATSIM for many years. I have used both Squawkbox and FSINN.

I have rarely seen problems with hovering aircraft, probably because most use FSX/FS9 and a flat airport.

 

I have recently transitioned to X-plane and what a fantastic simulator!

As the ground model is different in X-plane I recently went to CYYT and observed a B777 online, which was hovering some 5-10 m above the ground.

Is there no way of syncing this properly such that altitudes from VATSIM are corrected when the aircraft is on the ground?

 

I tried flattening but saw the same issue at LOWI default showcase scenery. FSX B737 were half underground

 

It is very disturbing to an otherwise very realistic simulator when this happens, and makes online flying less interesting.

 

Thanks in advance.

 

/Stephen

[Ernesto Alvarez 818262]

Been a while but i think there was a settimg in xplane, sloped runways or something like that

[Bradley Grafelman]

As the ground model is different in X-plane I recently went to CYYT and observed a B777 online, which was hovering some 5-10 m above the ground.

Is there no way of syncing this properly such that altitudes from VATSIM are corrected when the aircraft is on the ground?

Reminds me of the time during a busy fly-out with a VA I used to fly for. To follow "the company traffic turning right into Bravo," I had to turn on labels in FSX and guesstimate where his tail ended since he appeared to be subway-taxiing underneath the ground.

[Stephen Odgaard]

Been a while but i think there was a settimg in xplane, sloped runways or something like that

Unfortuanately this only solves the problem partly.

 

This should be solved through the XSB application, or even better coordinated across all FS connection applications.

[Niklas Belsing 1170456]

I think i read something about this being that either your or his/hear altimeter is set incorrectly don't know if its correct

[Keith Smith]

Different sims have different reference points for reporting their altitude. As a result, the only sure fire way to fix this is to know when a plane is on the ground, and in such cases, ignore the altitude that's being reported and instead draw the plane, clamped to the ground. This involves knowing how high the aircraft's reference point is above the surface of the ground (that would need to be contained in the CSL) and probing the height of the ground at that point. Lastly, you have to smoothly transition from ignoring the planes reported altitude to using it at some point once it's really off the ground.

 

The work to do all of this is non-trivial. None of this would be necessary if everyone had the same terrain and visual models that matched one to one with the planes being used, but that's just not the case.

[Randall Girouard 1178078]

I think i read something about this being that either your or his/hear altimeter is set incorrectly don't know if its correct

 

Yes, I remember reading about this long ago --- altimeter ground settings on all aircraft need to be in synch

[Ross Carlson]

I think i read something about this being that either your or his/hear altimeter is set incorrectly don't know if its correct

 

Yes, I remember reading about this long ago --- altimeter ground settings on all aircraft need to be in synch

 

It depends on what you mean by altimeter setting ... if you're referring to the setting that the pilot dials into the altimeter, it has no bearing on this ... the pilot clients broadcast the aircraft's true altitude and its pressure altitude. They do not send out indicated altitude. So your sim has no idea what other pilots are actually seeing indicated on their altimeter gauge.

 

If you're talking about the actual ambient pressure value loaded into the sim's current weather configuration, then that could have an effect, because that will affect the true altitude value sent over the network by the pilot client. At that point it depends on how the pilot client (XSB in this case) determines the actual altitude at which to draw the aircraft. If it uses the "true altitude" value sent by the other aircraft, then the pressure setting used in that other aircraft's sim is relevant. However, if it uses the "pressure altitude" value sent by the other aircraft, and corrects it based on the ambient pressure in X-Plane, then the ambient pressure in the other aircraft's sim would not be relevant, since it has no bearing on the pressure altitude transmitted over the network. (The pressure altitude is always calibrated for 29.92 inches.)

[David Lovell]

I've found empirically that X-Plane's settings have to be for runways not to follow terrain (but remembering to change that back if going to VNLK!), VATSIM weather in XSB, and Kollsman set correctly. Then most other aircraft will be on the ground, with the occasional fixed wing one air taxiing past.

 

Things can get a little odd when VFR pilots are using CAVOK and 1013 hPa / 29.92 in to overcome the weather. I once arrived at Caen-Carpiquet in X-Plane in a C172 amongst some FSX traffic to find that for them I disappeared underground.