Hi,

The problem is on your construction of your curve with hard corners very near.
Is it normal that your curve is not planar ?
You want it or is it an error during construction ?

If it what you want, you can use the ReconstructCurve script to have soft curve non planar. 200 points are ok for example to have nice sweep.

If you want a planar curve, resize it to have a flat curve. The sweep will be OK next.

Thanks you Michael and Phiro,

Making the polygon flat (and reducing the circle radius somewhat to get rid of the mitered corners) solved the problem indeed!

The polyline was drawn around an existing body, some points probably snapped to close-by points of that body that were not exactly on the plane.

Great help - as usual!