Simple 3D buildings: To duplicate ways or not?

Streets GL has prompted me to look into multipolygon relations for 3D buildings.

I’m trying to see if the tagging can be improved for the Balmoral Hotel. This a hotel with a inner courtyard and a tower.

At the moment there’s a multipolygon (MP 1) with a building tag, it has the building as visible from the street as “outer” (way 1) and the courtyard as “inner” (way 2). If it wasn’t for the tower, we would be done here. And then there’s a building:part for the tower (way 3).

F4map is happy with this, but StreetsGL isn’t, it only renders the tower. Looking into this, the Wiki says that if there’s a building:part present, some 3D renderers will ignore the building itself. So this seems to be an issue with the tagging, not with the renderer.

So I think I need to duplicate the multipolygon so there is one with building for 2D rendering (MP 1) and one with building:part for 3D rendering (MP 2). Then I can keep any tags related to the hotel (such as its name) on MP1, but move tags related to 3D rendering, such as building:levels to MP2.

Should the two MPs have the same members, so way 1 and way 2 are both members of MP1 and of MP2, or should I duplicate the ways as well?

If I’m duplicating the ways, they should still be sharing nodes, correct? (After all, it’s the same walls)

5 posts - 4 participants

Read full topic


Ce sujet de discussion accompagne la publication sur https://community.openstreetmap.org/t/simple-3d-buildings-to-duplicate-ways-or-not/98946