Hi Michael,

In Rhino I started to re-construct the model by changing the degrees and control point of the curves (each segment). I managed to make a lot of single span surface.
That is the reason I thought the rials structure do interfiere with the sweep action.

Another doubt that I have is why the outcome of the intersection between my rounded cube and my lines projected, meaning the ''triangles'' that I am using as rials have so many control points on the curved segments. Rhino also gave me these curves with a LOT of control points.

I re-built them and then the sweep was much more cleaner. That Is the reason why I am confused by the ''- Sweep does not use the control point structure of the rail curves directly"

Thanks so much for your dedication