Currently, you have to model your meshes separately (e.g. door, window, tunnel) but you have given me an idea for a mesh generation tool that would complement the spline structure tool so I may add that at a future date.
Couple ideas, could be double side wall texture for rooms and floor so not each are the same style. This can get repetitive. Also have an idea for a larger scale office building but it would require a different angle for the walls depending on the floor level. For example the bottom of the building is larger and then can either be curved or angled vertically if that’s possible. I have other idea for you to have a selection of window types that can be called from a variable so your not just stuck with one same for doors too.
Double sided walls and floors are something I'm looking into but it's not straightforward to do automatically (although fairly easy manual operation). Looking into the idea of a generation tool for structure parts as well, for different doors, windows etc.
