I've got a bit of experience using Mach3 (and Mach4). I am trying to set up a large 3D printer that is using Mach3 and an Ethernet Smoothstepper. I am not able to change out the hardware. I could potentially use other software other than Mach3.

The machine has a Z, X, and a rotary A axis. Currently, it uses a custom CAM program that has many issues and is not well maintained, which is why I'd like to use it with Cura, a feature rich 3D printer slicer (CAM).

So I need to either figure out how to set up Cura to output polar coordinates (a combination of radius Z, angle A, and height X) or I need to figure out how to get Mach3 to accept an XYZ coordinate and map those itself to a corresponding radius, angle, and height. I don't think Cura is able to output in polar, those calculations are usually taken care of by the printer's OS (Mach3 in this case).