FSX Elevated runway, mesh problem

I am not very good in mesh design hence I was trying to fix this issues in many ways, including Sbuilder flattens, FSX KML double flattens (top and botton), AFCAD flattens, some SCASM flattens... There is however still a problem. I don't understand why my terrain goes actually higher than the top flatten, which causes ground to be visible on the first screenshot, through the concrete. I would appreciate any suggestion, link or whatever you can share... I guess I am doing something stupid, just can't figure our what...



Resource contributor
Hi Stanislaw,

unfortunately that's a problem with the way FSX interpolates between adjacent elevation points, it's like a damped sine wave. Similarly, if you have a flattened lake next to a steep cliff you can often see the shoreline elevations dipping below the level of the water flatten.

You could experiment with splitting your flatten into smaller segments or adding a sloped flatten between the top and bottom poly, making sure that adjacent polys precisely align along edges without gaps or overlaps. Another approach is to force the flatten priority of your lower (=waterbody) poly to be higher though that might require custom entries to terrain.cfg.

In cases like yours it's probably better to not rely on terrain flattens and use a hardened platform in the model instead.

Cheers, Holger
Hello Holger.
Thank you very much for your suggestions.

I am using a hardened platform indeed, but I am also using an invisible SCASM runway for runway lights. And it does flatten the surrounding surface resulting in an effect from the 1st screenshot... That was the only reason why I have inserted an additional top flatten.
Thank you Holger, thanks to your suggestion I was able to achieve a result I needed.

I've simply used 3 flattens - at 0m, 2m and 3m. It works just perfect at the 2m resolution.