Hi Alex,

It looks like the problem I mentioned before: the Sweep command in MoI (which the pipe script is based on) has limited accuracy. I examined the surfaces in both STEP files in MoI using Construct > Curve > Iso and then checking the properties of the generated curves. The isocurves of the solid exported from SolidWorks are very close to being circles and so are recognized as circles by MoI which shows a diameter value for them in the details area in the upper right corner. Doing the same thing on the "TEST ARCS MOI EXP.stp" shows that the curves aren't as close to being true circles, and so MoI just shows bounding box dimensions rather than a diameter value:



Have you tried exporting a STEP from SolidWorks without doing "lock tangents"? Is Pipebend still happy if "lock tangents" is skipped?

Another way to see what's going on is by opening the STEP files in a text editor and doing a text search. The SolidWorks file is made up of TOROIDAL_SURFACE entities. The MoI file just contains general freeform surfaces.

- Peer