Hi Pilou, that's an interesting plugin for SketchUp!

But does it only allow just one profile? A full 2 rail sweep in MoI allows as many profiles as you want, for example here with 4 profiles along the sweep:




The other problem with the one you show is that the result seems to be a bunch of triangular facets and not a true curved surface... It looks like that may be difficult to control the accuracy of the generated surface - how close are those polygons to the original curves for example?

When MoI generates a NURBS sweep it is refined to have an accuracy of 0.001 units from the rail curves, so the result very accurately hugs the rail curves.

- Michael