Hi Alex, so it is the negative z axis thing.

The difference between these files is that "LEG01 EXPORT SLD.DXF" has the normal for each arc's plane pointing in the +z world axis direction.

The file LEG01.dxf has some plane normals in the +z world axis direction and some in the -z world axis direction.

It's a fairly common bug for DXF reading code to not do the AutoCAD "arbitrary axis algorithm" properly on a normal that is pointing in the negative z world axis direction. It's likely that the pipe bending software has this bug in it.

It's possible to flip any arc with a -z plane normal to go in +z instead but this will have a side effect of reversing the direction of the arc after it's flipped.

Some CAM workflows need the arc direction to stay undisturbed so that's why MOI doesn't flip them by default.

But you can go to Options > General > "Edit .ini file" button and inside moi.ini in the "[DXF Export]" section set:
FlipNegativeZAxisCirclesAndArcs=y

That should then flip any arcs that have a plane normal in the -z axis direction to the +z axis direction instead and avoid the bug in the bend software.


Does it work ok once that has been set?


For Rhino there's an export option "Flip arc normals to +Z" that you can turn on.

- Michael