Places where things come down to a single point can tend to have awkward shaping.

Sweep and Network calculate the surface in fairly different ways - Network is kind of more like a loft through 2 directions at once, and sweep produces a shape by sliding the profiles along the rails, which can kind of give the rails more of a kind of "weight" to the final shape I guess.

Sweep would have probably made less of a problem there if the center line had more of the same kind of curvature as the bottom rails - in this case the center line is sort of more flat than the bottom part.

- Michael