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Edge lights not aligned properly with runway

M

marcoforfs

Messages
10
Country
italy
Hi all, I am experiencing a problem with AFLT:
The runway heading set in ADE is 50.20 degrees.
However, when I create the edge lights with AFLT, they are not aligned properly with the runway. In fact, putting the airplane on one end of the runway, the edge lights are at some distance from the rwy, see f1.png attached, but moving to the other end of the runway then the edge line moves towards the runway, see f2.png attached.

Do you have any idea of what is happening?
The ADE file is attached.
Thanks in advance.

EDIT
As an additional (maybe relevant) information let me specify that I modified the stock rwy heading: originally the heading is 50.86, I changed it to 50.20 for the purpose of our scenery.
I have checked that even using the default AFCAD with the default runway heading, edge lights are not aligned to the runway.
 

Attachments

  • HCMM_ADE9_EMMR.ad4
    HCMM_ADE9_EMMR.ad4
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  • f1.png
    f1.png
    1.4 MB · Views: 329
  • f2.png
    f2.png
    1.3 MB · Views: 320
Last edited:
It's not clear how you see any lights at all, since there are no runway lights specified in the ad4 file you sent. Nonetheless, I added runway lights and, surprisingly (to me) the lights were "skewed" as you stated.

At this point, all I can say is that Flightsim and AFLT are using different values for runway heading. I will investigate and get back to you.

Thanks for reporting this.
 
gadgets said:
It's not clear how you see any lights at all, since there are no runway lights specified in the ad4 file you sent. Nonetheless, I added runway lights and, surprisingly (to me) the lights were "skewed" as you stated.

At this point, all I can say is that Flightsim and AFLT are using different values for runway heading. I will investigate and get back to you.

Thanks for reporting this.
Click to expand...
My fault in the explanation:
In the ADE file, I deleted the runway lights, then I added new edge lights by AFLT (got the standard AFLT blgs). I did so because eventually I cover the default runway with custom polys, so the default lights get covered by these and are useless.
 
My initial suspicion was that it was a round-earth/flat-earth thing. But the same situation exists in FS9 which uses flat earth, so that's not it.

I have checked a couple other airports and the same situation exists, but to a much lesser extent so as to be almost negligible. The HCMM runway is on an almost 45 deg. axis, where the precision of some trigonometric calculations could be relevant. But, to prove that will take some time-consuming experimentation.

I will address this (or at least explain it) as best I can, but it may be a while.
 
Found the problem! I was on the "right track" above, though my exact suspicion was wrong.

Turns out AFLT computes light positions on the basis that the earth is a spheroid while Flightsim computes the positions of airport surfaces relative to the ARP as though they were on a flat plane. (The latter approach takes less processing power and, while it introduces an error relative to real-life positioning, if everything is calculated that way the error is not observable.) I have confirmed that doing the same thing in AFLT eliminates the divergence you reported.

Now, I've got to examine every calculation of light/3D model position in AFLT to determine which method should be used. So, it may be a day or two before I re-release. Resolution of this issue for users will involve only a recompilation of the project.
 
gadgets said:
Found the problem! I was on the "right track" above, though my exact suspicion was wrong.

Turns out AFLT computes light positions on the basis that the earth is a spheroid while Flightsim computes the positions of airport surfaces relative to the ARP as though they were on a flat plane. (The latter approach takes less processing power and, while it introduces an error relative to real-life positioning, if everything is calculated that way the error is not observable.) I have confirmed that doing the same thing in AFLT eliminates the divergence you reported.

Now, I've got to examine every calculation of light/3D model position in AFLT to determine which method should be used. So, it may be a day or two before I re-release. Resolution of this issue for users will involve only a recompilation of the project.
Click to expand...
Thanks for your effort!
 
I have just posted Release 4.4.1.0 to my website http://stuff4fs.com . While the mis-alignment issue was easy to fix (with a little help from Arno - you'll notice a couple new files in the archive), once done it highlighted a second issue that was somewhat more difficult to diagnose and fix. That is, if you were running P3D and you repositioned the user aircraft from a North American airport to HCMM or vice versa, the lights at the second airport were not on the ground but floating in the air. When the user aircraft is repositioned over a long distance, the ground elevation at the destination may take a second or two to stabilize. AIFP was not waiting. (It now does.)

Finally, I notice HCMM has P-VASIs. Currently AFLT does not support P-VASI. From descriptions I was able to access, It seemed impossible to reasonably represent P-VASIs in AFLT. However, after seeing how MS approached P-VASIs, I'm quite sure AFLT can do the same. So I will attempt to add P_VASIs in the near future
 
gadgets said:
I have just posted Release 4.4.1.0 to my website http://stuff4fs.com . While the mis-alignment issue was easy to fix (with a little help from Arno - you'll notice a couple new files in the archive), once done it highlighted a second issue that was somewhat more difficult to diagnose and fix. That is, if you were running P3D and you repositioned the user aircraft from a North American airport to HCMM or vice versa, the lights at the second airport were not on the ground but floating in the air. When the user aircraft is repositioned over a long distance, the ground elevation at the destination may take a second or two to stabilize. AIFP was not waiting. (It now does.)

Finally, I notice HCMM has P-VASIs. Currently AFLT does not support P-VASI. From descriptions I was able to access, It seemed impossible to reasonably represent P-VASIs in AFLT. However, after seeing how MS approached P-VASIs, I'm quite sure AFLT can do the same. So I will attempt to add P_VASIs in the near future
Click to expand...

Thank you very much for your effort: I installed the new edge lights on HCMM and it seems they work perfectly now!
Thanks again!
 
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