I have meshes with a lot of details (using Rhinovault for catalan vault's geometry structures. Effectively, I found a way to do it. It is drawing a small surface to intersect the walls, by projecting wall borders lines on the…"
Right now it is not possible to extend walls to meshes. I will add this request to the wishlist.
If you want to convert the mesh into a polysurface, it might take time depending on the mesh detail.
But also take into account…"