The rec design is no problem, already have that as parametric. If you look at the attached code the rec is from N10-N360. The rec is actually a 3 cut design with a base rout then inside profile and a v-cuter to square of the corners. This is an existing design that I am adding the lines to make one of my other designs. The lines are also no prob and the way I got around the problem of overshooting the lines is to break them up into 2 sections 1 way if they donít overshoot and another if they do (simple jump query) as for the line sets yes there will always be 4 sets of 4 lines. The line sets in the top left and bottom right are also the easy bit as they are always the same. As for how I work out the spacing manually the previous attached drawings are from Autocad. All I do is stretch the squares design out then extend or trim the lines and take the three sizes (labeled ab in my in previous post) add them together and divide by three gives me the measurement but as you said this is not so easy to do parametrically as in Autocad I can dump the lines anywhere and work it out. How I do most of my Gcode for a design would be to do what I want in Autocad and just convert that process into Gcode. I have yet to work out this design though. I have a basic understanding of the Gcode and have had no real difficulty working it out but this one has stumped me. Iím shore there is a way but as of yet I havenít found it. The problem is that the lines wonít always be on the same plane. Have attached the Gcode and a pic of what the design looks like.