Pilou -

I made that test using LineWeb.

The issue is, the Loft function combines any coplanar planes into single faces, regardless of what method was used to construct the loft polylines. And that breaks Max's SubD.

Although I think if you export the OBJ, re-import and use Michael's SubD, it works. However as Mauro points out, that's a long back-and-forth process if you're tweaking a design.

Ed Ferguson