I use adobe illustrator. S.W. will directly import AI files but you need to have AI running in the background. I have seen issues with this though with missing vectors. In which case I will export first as a DXF or DWG. Remember to check you importing units and you can choose which vectors to import if there is junk you don't need. I usually don't worry too much about size in AI and just scale once in SW. Hope it helps.