Hi AlexPolo,

It sounds like the pipe bender CAM is expecting analytic surfaces like toroids and cylinders rather than freeform spline surfaces. I ran into the same problem a few months back when trying to import a STEP generated by sweeping in MoI into a sheetmetal CAM program. You can solve this by using extrude and revolve instead of sweep. Those commands generate clean analytic surfaces. Of course, it's a lot more work.

- Peer