I wish I could magic-wand a spline into tangential arcs, so that when magic-wanding slabs or walls on a spline I got something like the red line in the picture, which otherwise requires a bit of old-fashioned laborious moulding profile hand-drafting on Archicad.
Red are the arcs quite closely following a spline not shown, blue the sectors that define their centers, green are arcs offset from the red ones; could be a wall thickness too.
[Magicwanding currently defines points along the spline so that the resulting chords will not deviate more than a given dimension from the spline, or whatever is set in Magic Wand Settings. The resulting arcs are not tangential at those points, so that transitions are not smooth, surfaces and linear elements are not continuous, and concentric arcs or thicknesses don't work.]
This actually involves a new line/polyline drafting option, a sequence of tangential arcs.