Hello I started a topic with a similar name in lazycam, one day ago, but I think that the problem is not lazycam, but mach3.
If this is a bug, it is a big one. I hope I am doing nothing wrong because I am not a long time user.
I attached a very small Gcode (around ten lines). This code works very well if a user uses the XY plane. I am using the XZ plane, and the gcode is allready prepared for that, so if anyone wants to test is, nothing is needed to change in the config of the machine, you only need to load the code.
The problem is the directions of the arcs. G2 and G3 codes are not being interpreted correctly by mach3. Some arcs are being done CW when they should be the way around. This can be seen in the toolpath window.
As can be seen on the picture that I send, some arcs are OK, others do not. For an example, if you check the gcode line that appears on the window of the code (N70) it refers to a G2 code. What we can see on the toolpath is a G3 code!
Filipe