The flatten polygon

FS2000 features a 3D mesh terrain. Since ground polygons can only be drawn on horizontal surfaces, the terrain around the airport must be flattened.

You must create a flatten polygon for every airport or scenery you create with GroundMaker. That polygon is invisible, but it will make the inside of it flat in FS. This very important in order to get rid of visual artifacts. If you are working on a default FS airport (always flattened by default) make sure  your projects' altitude is identical to the default airport altitude in FS. Since you can't measure the ground altitude directly, you must try a little bit. To check that you've got the right altitude, make a flatten polygon and add a runway. Compile, install the scenery and run FS. Slew your aircraft to the ground. In exterior view, check whether the wheels are stuck in the ground (flatten polygon too low) or if they float above the runway (flatten polygon too high). You must try a little bit here...

 

Notes on drawing flatten polygons

You can only create one flatten polygon for every project. A flatten polygon should be convex and have a max of 9 points.

 

Setting  properties

There are no options available. Flatten polygons are invisible. Set the altitude at which the terrain mesh should be flattened in the project settings (FILE\ PROJECT settings... menu item, LOCATION tab).