i have a prety large 3d model done in acad 2000, its on a thumb drive, i wanted to see if sw 2013 premium  would open it. i put the thumdrive into the usb port, found the model and clicked open , sw started opening the model. it took a couple hours and i decided something is wrong so i stopped the process. what happened is sw converted all of the acad models tp sw but didnt finish, when open most of them there isnt anything there. the ones that do open are a mess, they have these big o rings around them, the parts that did convert are "imported" and cant be resolved. the bad part is sw didnt make copies of the original models they are all usless sw models now. can i reverse this process and get the acad models back? or is there a way to continue with the sw conversion?