Hello guys, I decided to split this thread: http://www.fsdeveloper.com/forum/threads/terrain-flattening-at-lpma-and-gp.440754/ into two sepparate ones for more clarity. Here is my problem: I have opened a small FSX:SE default ARP within ADE (e.g. LRTR) and fixed some of the wrong or missing taxiways using a sattelite img created with SBuilderX. I then added some "custom ground lines" and some "custom ground polygons" etc. My work can be found here: https://library.avsim.net/esearch.php?CatID=fsxscen&DLID=199206. The entire ARP including all the ground lines and the polygons and also the AI show and work flawlessly in FSX:SE! Compiling the same project for P3D v4, the ARP is missing some features. All custom ground lines and custom ground polygons are missing. Furthermore, if I open any DEF ARP from P3D v4, add a custom ground line, compile etc. I don't get to see that line. Now since I did it right for FSX:SE (because I can see them), I have no idea what's wrong in P3D v4. I only use the stuff within ADE (no sketchup, GMAX, and other voodoo things ). Could you pls advise me? Thank you from lake Constance, Gerald.