I am a little new to scenery creation. I have read the term 'flatten' and I think this is what I need to do in the area I am creating. Is 'flatten' a program (exe), or a command of some kind? Any help will be appreciated.

"flatten" is the term used for scenery terrain that is modified so that it does not follow the underlying elevation mesh; rather, it is set to a single (in most cases) elevation. The main reason for "flatten" is to set airports and water bodies to a single elevation. A second reason is to cause streams and roads to appear better within the terrain.The methods used for obtaining a flatten have changed over the versions of FS. The following are common:1. Use of a "flatten=" line for a scenery area folder in the file scenery.cfg. This is probably the easiest way to do it.2. Since about FS2000, there is a command commonly called "Area16N" for creating flattened terrain. This command is used with the SCASM scenery compiler with creates scenery bgl files.3. There also is the ability to create vector polygons to define areas to be flattened. This is the method used in FS2002, FS9, and FSX. These polygons are often called land-water masks (LWM). In the FS9 default files, they are compiled into either HP9 files (oceans and water bodies -- hydro polys) or FL9 files (flattened airport areas). In FSX they have been combined into CVX files.All three of these methods define flattens in terms of lat/long and elevation.4. The stream and road flattening effect is set up a little differently. It is controlled by the terrain.cfg configuration file. Note that any changes in terrain.cfg have global effect.A major problem in FS9 which has (thankfully) been fixed in FSX is that areas which have been flattened cannot be unflattened with addon scenery. The original files must be modified.scott s..