General Polygon Flatten problem

Not totally sure if this is the right place, if not please my apologize and happy for an administrator to move it to somewhere else.

Please note that I have been fighting with this already for 10 days or more, so I've tried lots!!.

Background information.
Using P3D4.4
The photo scenery you see is mine, produced with SBuilder
Airport is LECO (Spain), is based on the default airport. I had to move its location a bit and so on.
FSGlobal as mesh
There is a polygon in the ade file excluding the default airport working fine.
The polygon highlighted in ADE is a general one, flatten and slpped. The inner vertex are all at the same altitude and the outer ones vary but are based on the simulator readings more or less. NO VERTEX IS SET AT 0m, checked a thousand times!

The most obvious one is that vertical wall triangular shape in the middle of the pic. It shows up when using the flatten poly. With the background poly only, obviously, nothing happens.
Interestingly, at the opposite far end corner of the rwy it happens the same.

Various Checks so far
Using the priority check, no other file seems to be interfering.
Deleted and reconstructed the flatten poly totally or partially using more than one flatten... various options already done here.
Changing the position of the vertexs, wider coverage, smaller, different altitudes...

I'm stuck, I did try a lot more things, but the relevant ones are above. Could anybody help?

Please feel free to ask for more info if you need.

Thank you




Staff member
FSDevConf team
Resource contributor
Did you try to use multiple flatten polygons? This one is concave in shape, maybe that's part of the problem.


Staff member
FSDevConf team
Resource contributor
It seems your polygon has a kind of U-shape around the runway. So that makes it concave. Given where the weird elevation showed I thought that might be part of the problem. So you tried already with a few more simple polygons that are convex?
Yes, but note the other corner is also rounded and the outcome is good, if I understood properly. In the picture, is just one poly, but today I cut the U shape in halve, I mean I used two polys. The fact is that doing so, all was messed up, terrain full of spikes and so on,(like in many other trials) but made no difference any way.

Remember, and I found this interesting, the same happens in the opposite corner at the far end of the rwy.

Seems like something is hidden perhaps out of the ade environment, something geometric that is cutting those two corners.... honestly totally puzzled...

Thank you Arno anyway for your help
I think the problem was overlapping with the main airport background. See the picyure attached "project" to see how I sorted it.

However, I have another problem now. If you see the two pictures, you can see that for some reason, when I compile the project, the polygons are not compiled. I checked the folder settings to the relevant SDK and are correct... puzzled... Sure I'm doing something wrong but I can't see what...

Any suggestions?

Thank you