What sets the XY:UV separation distance in a GCode file?

Mine is version 2.7.14

I see the foam.ngc located at /linuxcnc/configs/sim.axis/foam.ngc.

The XY_Z_POS and UV_Z_POS was already in there but not responding to changes.

In a hurry, I hadn't noticed that the path to load that file was relative and set to "./foam.ngc". I copied it over to my machine config directory and it picked right up and now displays correctly.

It never threw an error saying that file wasn't available.

Problem is that it looks correct on the startup axis screen with those squarish things loaded. When I load one of my cut files it immediately goes back to the 38.1mm spacing.

I can restart LinuxCNC and it looks right again until I load my files.

You need to put those comments in your cut files.

I have:
(AXIS,XY_Z_POS,0)
(AXIS,UV_Z_POS,500)

At the beginning of my Gcode as well but it seems to make no difference.

When I load my Gcode (and it goes back to 38.1mm spacing), I see those lines listed along with the other GCode down in the code console under the axis display.

Is that the wrong syntax? I tried other forms and it ignored that as well.

I copied the beginning of the foam.ngc into my cutfile and it worked.

I needed:
G17 G21 G90 G61 G54
(AXIS,XY_Z_POS,0)
(AXIS,UV_Z_POS,500)
(AXIS,GRID,5)
G0 x0 y0 u0 z0