Hi.
I have been fiddleing around with Edgecam for about a year.
I still get confused over this.
When designing, I used to draw like the machine was operating, X+ and Z- (lathe with live tools, Fanuc 18i).
I had to correct G2 and G3 in post, and it worked fine for 2D turning.
Mill operations like G112 and G107 have never been working, correctly.
I then swithed to always design in Z+ and X+, swithed the Z from + to - in post and corrected G2 and G3 back to default, then turning and milling output became close to perfect, but still I have a problem.
G2 and G3, when using I and K, is reversed, like K1.0 becomes K-1.0 and so on.
I have to choose reverse axial for a bore tool, to have it correctly, which I feel is wrong.
What am I doing wrong?

i'd suggest you design in Z- and X+
that would be the same quadrant you want to machine in.

designing in Z+ and X+ seems some kind of backwards to me...

You're right.
Depth in part, always Z-, simple but it works.
I found a solution that works for me.
I have saved the semi-working post 3 times, given a name like Turn, G107 and G112. Then I can keep my focus on the actual operation/problem, like turning, milling, milling rotary.
It works for me :)