Hi Guys:
I have some testing to do for some of this, but the LH side I can explain. Imagine the whole piece, left to right is first expanded by the clearance, so it grows , this is done to make to tool cut
only to the clearance + Tool radius to the part. But the LH side expands to the left when this is done as well as the rigth expanding to the right. So the initial rough pass tries to cut to the expanded left side, which makes it cut further. This is actually helpfull if th etool has to step to the right each pass ( on the left hand side..). It means if a profile is say 100mm long, the initial ough can be say 120mm after expanding the profile. ( Imagine a tool offset comp in mill applied to the profile.. ).
Its hard to explain what I mean, Ill see abotu showing you the actual usage of the subtraction and clipping masks to make it clearer..
Is that dxf from Chips example posted? I think I need to run that, the offset is definitely wrong, looks way short..
Art