there's also a seneca script that creates tubing on the path of the selected edges. Alongside beveling and deleting inward polys and making tubes out of remaining corner polys, I saw him using that 'makepipe'(or somthing else) script too.
It's funny, but I personally, rarely used max splines to create tubes. I used it to create... arches! Gothic, Moorish, Moroccan, and other similar, which are not simply half circle. And that is one thing I find quite difficult to do in modo.