Hi Steve,

The error you talk about is more to do with continuity right ??, I did actually match & improve on G0 in Rhino but I wasn't
happy with the result due to the surface isocurves going to a single point, thats where I lost the control.

Building the surface as one is usually the best option in terms of overall smoothness and your first comment the other day
was 'spot on' as splitting the profile helped make a good surface as shown in your analysis. I say good because if you turn
the surface and look end on there is a crease when the surface again meets at a point.

Are there any other ways to build such a shape or how might it be possible to further smooth your example ?

Many thanks in advance,