Michael,

I see. Very enlightening!

But I seem to get just the same result with Network, which I understand to be a sort of Sweep in two directions simultaneously. With the advantage of being able to add more than just one rail in order to better control the output.

On the topic of what I find frustrating and might like better/smarter tools, there is the curve rebuild function. To help ensure smooth surfaces, it pays to have "perfect" curves. I have taken the habit of generating curves with liberal use of the Blend tool and to otherwise rebuild curves. I never know how many points to ask for that would simplify/smooth/fair the curve while preserving the general shape of the original sketchy curve. A sort of clever interpolation that would minimize deviation from the original curve with the least possible number of points to sooth out the shape would be more than nice to have. Or is it there already somewhere and I simply missed it so far?