Thanks Michael for the investigation - perhaps its just the larger radiuses Ill keep on mental tab on when Moi Fails see if I can pick up the pattern. When it does fail I usually import the same DXF pathway and import that into solidworks - so that all makes sense that there is an underlaying difference on how different surfaces are created. I have tried to contact the Pipebend software developers but they are in China and no reply. With tube bending most parts are 3d so thats why you need to import a 3d STEP file. On this spiral file its 2d but in the pipebend software I overide the rotation on each bend and end up with a 3d spriral. Ill send a picture of that once its bent.

Here is the same machine we use in action to give you a better idea of the process. Some thing like this part in the video I can design that part in MOI in a couple of minutes it really is a killer app for this type of work.

https://www.youtube.com/watch?v=178HPP3v3x4

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

Thanks Peer I tried to simplify the shape as the outer shape can either sqr or round ultimately the machine doesnt know which tool set you put in but still same problem - here is another part created in MOI with essentially the same components a few 90 degree bends - a few straight sections and 1 large arc this file imports into the tube bend software without problems - strange that it work most of the time but with the occasional file its a no go - Ill keep experimenting see if I can pinpoint the issue.