I tried smooting, and fail to see how it would help here, with moving CPs normal to the surface, as the U/V hull curve flow is just like it should be. I found out that with DragMode set to the UVN option, and using DragStrength, at least no woodpeckering with the prehistoric MoveUVN tool is necessary. Still, blending or fall-off in a surface matching tool is essential.
A Sweep 2 rails alternative by nature has the “wave” transition, but too many spans and too many CPs to make detailed adjustments.
Rebuilding the Sweep 2 rails surface is no option, as the shape changes a lot; see the cross-section inflections, and the isovcurves no longer matching up, like the Surface from four edges provides out of the box.
