My understanding of what he's asking is if you create a line using two individual segments >joined together< and then sweep that, you'll get an object with a break or seam where the two lines were joined. (Technically even though the two individual lines were joined into a single line, there still remains a >point< between the two causing the seam)

If I'm correct, then it's a matter of showing the points on the line and deleting the >center point< of the two joined lines before performing the sweep thereby creating a clean singular surface (I have to test this theory - my dev machine here doesn't have an internet connection...)

I've run across this as well but know how to "avoid" it. But basically when a two objects are joined, they're not made continuous (as in the case with two simples lines joined together for example) so instead of two points after the join, you get three.

I feel it would be great also if join actually made an the two objects continuous (at least an option) - which would remove the center point between the two lines following the simple example, but I'd imagine this may not be>simple< for every kind of join?

-Will