This evening I have been working on a feature for gPoly that will make it a lot easier to draw curved edges of your ground polygons. By using Bezier curves you don’t have to add many points to get a nice smooth curve. All you have to do is set the begin and end point and use a couple of control points to determine the shape of the curve. In the images below you see a few example I made while testing. The two points at the top are the control points that determine the shape. You can see that by changing their position, the curve has changed.
As you can see from the images I can draw the curves in gPoly now. Tomorrow I will continue working on this feature and check if the texture mapping is assigned correctly and see if exporting works fine. But I am sure this feature will be very useful when drawing your airport layout.