It's been 4 years and we still have to use the forest edge map workaround in corona!!!
So I converted to vray and still the edges were not working as I am using a surface- the workaround being to add a spline.
Ok...
I create a spline, but then the workaround notes to use the spline
instead of the surface cancelling out the point of using the surface in the first place.
Is this really how this works or am I missing something? How can such basic features still be missing?