You May want to consider my answer in this 3d
https://devsupport.flightsimulator.com/t/3348 The current mesh system Is
limited by the resolution of the grid underneath It , you can take see It by
enabling the wireframe settings in the Dev menu. Basically, the grid Is
aligned north-south, so any terraforming aligned to the girld Will give you
straight edges, any rotation Will give you a some jagged edges You can’t avoid
It, it Is the way . You can minimize the effect by adding some falloff (aka
smoothing) . Or you Can Hope in a higher definition grid, eventually they Will
manage to obtain that, dunno It Is mesh related. As per @superspud answer, if
you Need a perfect shape, go for the 3d solution, you can borrow the sat
imagery for your textures and plant some “fake” grass, most users Will not
notice it