Incremental Axes U, V, W support?

Hi

I'd like to use LinuxCNC to simulate some lathe g-code before I run it on my actual machine. 
I have linuxCNC installed, and have the gmoccapy lathe simulations installed, but when I try to run my g-code, I get an error about "invalid character U". My physical machine has incremental axes U and W that correspond to X and Z. U and W are incremental moves, and X and Z are absolute moves. So if you're at X1.0 and you move U3.0, you'd end up at absolute X4.0, or if you're at X1.0 and move U-3.0 you'd end up at X-2.0

Does linuxCNC support incremental axes like U and W? Do I need to set them up somehow in the simulation machine's HAL file?

The gcode interpreter will only accept axes you have configured in your ini file. The live plot in the gui will add translation in U,V,W to position of X,Y,Z respectively.
Note that you will need to add 'U,V,W' to the GEOMETRY entry of the [DISPLAY] section in your ini file.

See 'configs/sim/axis/axis_9axis.ini' for an example configuration.

I've added U and W to the G7x cycles, but those letters cannot be used outside the subroutine interpreted by those G7x codes.