Water flattens islands

[rsubers2]

I am on P3D4.5 although this problem is in previous versions as well. It appears that a flatten flattens the area around it, not just the area in the polygon. This makes it difficult to do islands with steep sides. The flatten in the water polygon flattens the island. Has anyone come up with a way of working around this? Specifically it would be nice to have a flatten that stops flattening at its borders allowing steep sides beyond.

[LimeSim]

Not sure which GIS program you're using to create the flatten polygons.
SBuilder offers you the option to slice polygons by a certain QMID size. The smaller the QMID size you slice it to, the more likely it is that the flattens don't "invisibly" extend anywhere where they don't belong.

Note that this will most likely destroy your Z-values in case you created a "3D" polygon with elevation values at each vertex point.

[rsubers2]

I am using SBuilderX 3.15 which as far as I can tell is the latest version. I do not see a QMID option for vector polygons either on the menu when I right click the polygon or when I select properties from that menu. Any suggestions?

[downscc]

You will have a wider audience if you take this issue to the FSDeveloper forum.