Measure from the bottom up?

[WillAdams (William Adams (Carbide 3D))]

Yes, that is it — for a bit more on this sort of thing see:

Preparing rough cut lumber for machining

Given a rough piece of stock: [20240204_151557] one sets it on the machine, and if need be, adds shims where/as needed to make it as level as possible. and clamp in such a way that the entire top may be surfaced off [20240204_155540] set zero, then begin cutting: [20240204_171001] After running the file once: pocket_464x116_1mm_LOWERLEFT_TOP.c2d (44 KB) if a repeat is necessary, jog down to zero, then down by the cut depth of the file (1mm) set zero there and repeat — the zero may be …