Hi Bruno,

> I mean the result between making the model in Moi and importing the lines from Rhino
> and making the sweep in Moi...seems to be the same.

Yes, that does make sense for the case of using Sweep - Sweep does not use the control point structure of the rail curves directly, a sweep is formed by an iterative refinement process which means it's only really the shape of the curves that is important not particularly how many control points are in it.

It looks like the problematic part of your sweep is a bend where the radius of the bend is tighter than the width of the curve going around it, that tends to produce a bunching effect similar to this:



- Michael