Railing as a zone boundary

[Karel Landa]

I think I have posted this in old Wishlist but it did not make it here, so here I am again.

Often there is a situation in which we need to create a zone/space outside of the object such as balcony.

If I want to stick to automatically place zone based on boundaries or reference lines, I need to create a Line/Polyline defining the space. But in case of the balcony, there is usually a Railing. Why not to use this Railing as a zone boundary?

[rakurs]

Not only railing - if arbitrary LINES can be zone boundaries, why can't slabs? Most objects could in fact be zone boundaries and it would help reduce errors because lines which are used for example to separate Living Area from Dining Area (in open space floor plans) can get behind elements and produce wrong results.

One other reason for slabs: different floor finishes! In the above example, tiled area would be one zone, and parquet area would be another.

Also, stairs...