// Docs

Heights and depths

Heights are measured from Z zero. With Z zero on the stock top (the default), cuts go below zero; with Z zero on the table, the stock top is at the stock thickness. The file says which (in its header).

Clearance, retract and feed height above the stock; the cut below it.

Height	Used for
Clearance	Rapids between operations, at tool changes and at the start and end. Set it above clamps and vises.
Retract	Rapids between cuts of one operation — lower than clearance, so less time in the air.
Feed height	Rapid descents stop this far above the surface still to cut; the rest is fed, never rapid into material.
Start depth	(per operation) cutting begins this far below the stock top, when the material above is already gone.
Own safe heights	(per operation) its own clearance and retract, for example over a tall clamp next to one feature.

Depths

Depth is how deep an operation cuts from the stock top. Stepdown splits it into passes. A cut-out profile goes a little below the stock (0.4 mm by default) so the part comes free; the safety checks flag any cut that goes below the stock bottom into the table.

At the end of the program the tool rises to clearance and waits where you choose under At the end: over the last cut, at the work zero, or at an X / Y.