If using simple polyline for hub and/or shroud - e.g. for imported meridional geometrie - this curve can be converted to a Bezier curve. Thus it's possible to make systematic modifications of existing geometries.

First the desired polyline is imported via Import from file.

The imported curve is displayed red, the original curve blue.

By pressing the Start! button the position of the Bezier points is calculated in such a way that the imported poyline is replicated as exact as possible.

The number of iterations can be varied if required, whereas the default value of 10 normally results in sufficient precision.

The precision of the approximated Bezier curve is displayed as Max. and Mean distance from the imported polyline.