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FS2004 PAPI 3D calculation

H

hgschnell

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1,604
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germany
Dear Don,
some of us use ADE PAPIs and your 3D Papis.
You would help us a lot if your calculation could be a little bit more matching the lights.

Now it looks like this:

https://abload.de/img/papi1iaja2.jpg

Is is a little tricky to change the PAPI by AFLT4 to match the ADE PAPIs.
 
Guenther. how do you know that it's the AFLT lights that are out of position? Have you measured the respective offsets from the runway centerline?

While I appreciate
Is is a little tricky to change the PAPI by AFLT4 to match the ADE PAPIs.
Click to expand...
There would seem to be little I can do about it other than provide the ability for you to manually match the two as I have already done. The stock PAPI's are placed by Flightsim at a position that may be edited by ADE. AFLT uses the same value in double-precision calculations that controls Flightsim.
 
gadgets said:
Guenther. how do you know that it's the AFLT lights that are out of position? Have you measured the respective offsets from the runway centerline?
Click to expand...
I realised it on several airports and it is easy to recreate and test.
Using the ADE offsets in your AFLT4 calculations places the 3D objects not exactly to the same coordinates.

I think the picture shows it clearly.

here is another one:


Anyway thanks for your fine AFLT4, it is a great tool for airport lights!
 
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Using the ADE offsets in your AFLT4 calculations places the 3D objects not exactly to the same coordinates.
Click to expand...
Yes, I realize that. AFLT uses the same dimensions as FS9 (distance along and offset from centerline). That AFLTs PAPIs don't appear in the same position as FS9 suggests one (or both) are not in the correct position. AFLT uses double-precision arithmetic, so I suspect it's the FS9 ones. (I don't know how FS9 places its PAPI's, Perhaps it just uses integer arithmetic.) In any case, to match the height of FS9's PAPIs would require a 3D model of unrealistic height and rather odd looking.

I'm leaving on a short vacation tomorrow. When I return, I'll take another look at the issue to see if I can discover how FS9 places it's PAPIs.
 
Yes the offset is a problem, but one that can be fixed by setting a specific X and Y offset from the ADE values. That is usually close enough. But I believe most of the problem is the height issue you mention, which causes the FS9 lights to look offset from various angles. I'm not sure how that could be fixed, since it is a parallax issue. I position the AFLT lights so they sit on top of the default lights at about 500 ft AGL while on final approach. This gives me the least overall error to my eyes.
 
Thanks for the suggestion, Tom. Nonetheless, I'll do a little experimentation since I'm now back at my development system to see if I can:
  • first of all, determine how FS places its PAPI lights (it doesn't appear to be a precise utilization of the ADE-specified parameters, since AFLT's is and there's still an offset) , and
  • then see if I can reduce the offset.;
 
I have done some analysis at one of my airports. AFLT PAPI lights appear exactly as specified. The offset between the AFLT lights and the FS lights appears to be about 1 m. That offset appears to increase slightly with each light outwards from the runway, which suggest FS spacing is not quite correct. Please note, however, this approximately 1 m. offset is not consistent . It appears to vary slightly from one runway to another.

There is an option on AFLT's Main Panel that controls whether or not the stock PAPIs are purged from the airport .bgl. If not checked, AFLT should apply a 1 m. correction to the lateral offset from the runway. It's possible the logic is reversed.

Guenther, please confirm whether or not the option is checked. Also, please change the selection and see if the offset changes.

It appear that there is also a small vertical offset of about 2-3 cm. I haven't yet investigated whether the 3D models and lights can be elevated by that amount.
 
Thanks Don,
the reference file of my picture does not exist anymore...

So I began with a stock airport VOHY.

https://abload.de/img/vohystockfs9cnjh0.jpg

Now the ADE9 version (nothing changed)
Stock:
<Vasi
end="PRIMARY"
type="PAPI4"
side="LEFT"
biasX="28.96M"
biasZ="762.91M"
spacing="91.44M"
pitch="3"/>
<Vasi
end="SECONDARY"
type="PAPI4"
side="LEFT"
biasX="28.96M"
biasZ="712.01M"
spacing="91.44M"
pitch="3"/>

ADE9:
<Vasi
end="PRIMARY"
type="PAPI4"
side="LEFT"
biasX="28.96M"
biasZ="762.91M"
spacing="91.44M"
pitch="3"/>
<Vasi
end="SECONDARY"
type="PAPI4"
side="LEFT"
biasX="28.96M"
biasZ="712.01M"
spacing="91.44M"
pitch="3"/>

https://abload.de/img/vohyade9fs9afkbo.jpg

Now the AFLT4 version:

https://abload.de/img/vohyaflt4fs9c0jkf.jpg

Now with the purged ADE9 version:

https://abload.de/img/vohyaflt4purgedfs9byj27.jpg

And finally the version with unchecked "purge stock papi"

https://abload.de/img/vohyaflt4stockpapisnon5k1j.jpg

I cannot see any difference.

Sorry, that's all I can do.

If you need any files, just tell me.

I think it is easy to recreate...
 
No, don't need the files. But, it would seem the "Don't Purge ..." selection is either not being processed or is being lost. I'll take a look
 
I have just posted General release 4.5.1.6, which substantially improves the alignment between AFLT and stock PAPPIs when stock PAPIs are not purged. Note, however, the changes are implemented prior to compile, so you will need to Place VASI/PAPI for each unit and then re-compile your project.

It seems the offset varies from one situation to the next - in most cases not by much - but enough to make the fix imperfect in some situations. But, it's about t6he best I can do overall.
 
They are indeed offset; we had done some work on them earlier and was wondering if the this code change had altered things.
 
Without a detailed analysis of the code and code changes, it appears that both PAPIs and VASIs are affected by the recent change. However, it appears the re-alignment in elevation will not apply to VASIs. I can probably fix the latter if it's an issue.

Why don't you try it and see if things are better.
 
I fixed PAPIs - which is what you asked me to do in the initial post above - and for which I have not yet received confirmation of improvement.. I have never investigated VASIs, but I thought VAS1-2 might benefit from the fix. VASI-8 is another matter altogether and will require much more investigation
 
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