FSXA Ground Polys Disappearing

#1
I have added ground polys 1 thru 4 on runways at TAPA per the attached FSX screen shot. Polys 1 thru 3 disappear when zoomed in but 4 does not. The airport, background and runways are all shown to be at 60 ft elevation in ADE. The polys are at layer 23 or 24 with lines at layer 24. I would appreciate an explanation if one is available.

Art
 

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gadgets

Resource contributor
#2
Art, layering of ground polys is only relevant in FSX when polys are to be placed over one another. As you will note from other posts on the topic in this forum, GP visibility issues usually relate to the relative elevations of the ARP and the flatten or because the flatten doesn't extend to the location of the problem GPs.

Without your AD4 file and the airport .bgls, I can only speculate.

Don
 
#3
Well, I found that moving GP #1 away from the end of the runway would result in all GPs being visible when zoomed-in, and I added sloped flattens around the airport background flatten at that end of the runway. In real life the runway slopes toward the coastline, but in FSX there is a 60 ft drop-off. While the slopes from the end of the runway in FSX to the coastline looked okay as I had it, adding the sloped flattens has seemed to make the GP problem go away.

I'm not sure I understand why this solved the problem, but it is what it is.

Art
 

gadgets

Resource contributor
#4
Art, if you post your before and after ad4 files (or e-mail them to me if you're shy) - and the before and after flattens (if they are not included in the ad4 files), perhaps I can explain the "why". What would appear certain from your post, however, is that it was a flatten issue.

Don
 

gadgets

Resource contributor
#6
Art, I compiled your "old" file. (Didn't notice any significant difference between it and the new one in the area of Poly 1.) I don't have UT TAC. But with stock mesh, I was unable to duplicate your issue. Actually, I'm not clear what you mean by "polys disappear when zoomed in". However, I tried a number of different scenarios and noticed nothing amiss.

What I did notice is that your new airport background does not fully overlay the stock flatten. Consequently, the flattening applied in any position outside your new background but inside the stock flatten will reflect the stock flatten. But, that's probably not relevant to your reported issue.

Since I don't have UT TAC, I can't replicate what you have. But, as I've reported in various forums, a flatten is not always flat. I have on numerous occasions seen "ripples" near the edges of flattens, especially where they bound steeply sloping terrain. While these ripples generally are only a cm. or two in height, they are enough to affect the display of GPs in the vicinity. The effect is that at low angles of incidence, (portions of) the GP disappear. Perhaps this is what you are seeing. If so, I suspect applying a sloping flatten off the end of the runway would change things.

Don
 
#7
I don't want to deactivate my UT in order to verify what you experienced because a problem with UT is that everything that I customized reverts back to default when it is reactivated. I turned on an older computer with FSX to check this with default scenery, but the computer began installing Windows 10. When I get control of my computer again, I'll try it with default scenery, but I expect that I'll get the same result as you due to the different mesh.

There is an airport background exclusion polygon deleting the default airport background, but the default airport is at the same elevation and not a factor anyway.

The "ripples" phenomenon is interesting, but what I am experiencing is the complete disappearance of all GPs in a large area, some nowhere near the edge of a flatten. But, when the one GP near the edge of the airport flatten is moved away from the edge, all of the GPs no longer disappear. It's kind of like 3D objects disappearing when zero LOD takes effect with distance, except this occurs when getting closer rather than farther away.

Art
 
#8
My statement "the complete disappearance of all GPs in a large area" is wrong. This appears so when zooming in while in the top down view, but slewing at an altitude just high enough to see the GPs from a distance reveals that they disappear gradually and uniformly as you get within a certain distance. As stated before, this applies only to GPs 1, 2 & 3. GP 4 is not affected.

I finally did try it with my other computer without UT-TAC and got the same result, so I don't know why you didn't experience it when compiled from the "old" ADE file.

Art
 

gadgets

Resource contributor
#9
Art, I checked again this morning after receiving your message and discovered I had mistakenly used your new version last night (which explains why I saw no difference in the airport background poly of the two versions. So I tried again with the old version. No difference.

However, after finally realizing what you meant by "polys disappear when zoomed in", I first went to top-down view and, at an altitude estimated to be about 35000' all GPs disappeared. I then pointed the aircraft nose down and slewed the aircraft up until the GPs disappeared at 32,875'. My final test was to slew the aircraft (level) several miles back on approach and, sure enough, at about 6.1 nm, poly 1 disappeared. Poly 4 disappeared somewhat before that. Polys 2 and 3 can't be seen at that distance. You may not have noticed that FSX first displays runway details at about the same distance.

It then occurred to me that those distances all equate to about 10,000m which, I understand, is the maximum distance at which GPs are displayed and, as such, is the distance programmed by ADE-GP unless you specify a shorter visibility distance.

Hope this clarifies.

Don
 
#10
Don, I have no issue with GPs disappearing in the distance. My issue was with them disappearing when I got close.

The following view shows two of the three at issue GPs visible in the distance:
tapa1.JPG


The following view shows the XX disappearing as I get closer:
tapa2.JPG


The following view shows the XX completely gone as I get closer:
tapa3.JPG


The following view shows the concrete GP disappearing as I get close:
tapa4.JPG


The final view shows the concrete GP completely gone with a closer view:
tapa5.JPG


These views were from FSX without UT-TAC, and as previously stated, moving the concrete GP away from the edge of the airport flatten eliminates the disappearing of all of the GPs. Adding more airport flattens took care of the problem so it is no longer my issue. I just wanted to clarify to you.

Art
 

gadgets

Resource contributor
#11
Well then, we're back to "Square One", because I am still unable to duplicate. I positioned the user aircraft where it appears to be in your screenshot and slewed it up and down. The GP's remain.

That you've fixed it by adding some flattens suggests whatever you are seeing is related to ground elevation. But, whatever it is, it's not affecting my system. Perhaps someone else can duplicate and explain .

Don
 
#12
A while back a had a similar, but not the same issue--I was "loosing" GP at the ends of a project. With Don's help, we tried various alt adjustments without help

On that project, changing the GP compiler option fixed my issue--see attached image

http://www.fsdeveloper.com/forum/th...d-line-not-showing-in-fsx.435728/#post-728103 is, I hope, the link to that discussion (nov 15 2015 if my link does not work)

But I am not at all certain this is the same issue
 

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