Bremer Dom - bug?

[hjanetzek]

For relation 2788481 of Bremer Dom which looks correctly modeled the OSM2World converter produces weird results

[hjanetzek]

[tordanik]

This building is too complex for current 3D building specifications.

In particular, roof lines and building parts do not really mix yet:

• You cannot use them together with vertically stacked building parts – because the only connection between the roof line and the building part outline is that the roof lines are within the outline, and that's true for the parts below, too. (This is the reason for the roofs "within" the towers.)
• If a node of a roof ridge is part of multiple building outlines, this also doesn't work yet.

Furthermore, OSM2World does not know the tag building:cullis:height. It is not part of Simple 3D Buildings, and I wasn't even aware that it had a wiki page until now.

If you want this to be rendered in today's applications, my suggestion would be: Save your current mapping offline for future use, and build a simpler representation using only Simple 3D Buildings roof shapes for now. Of course the complex real-world roof cannot be accurately modeled with that alone. However, it's an approximation – and for some parts the roof lines are even unnecessary, such as the Vierungsturm which seems to have a straightforward roof:shape=pyramidal.

[hjanetzek]

Thank you for the explanation. I did not do the mapping - It seems it was a very ambitious mapper if that tag cannot even be rendered, I will forward your suggestion. There are already a few uses of cullis:height even though not that complex: overpass map for cullis:height

I was actually looking for options to improve rendering of buildings in my application. Have you thought of providing building obj models for those building that cannot be rendered by simple extrusion? This would ease embedding in simple 3d map viewer applications a lot :)

[hjanetzek]

nvm about the .obj service. it's just that I render the map from a osm2pgsql database, but for building models it would be no problem to fetch the data via Overpass-API.

I'm wondering why there is no roof:shape=round in simple buildings draft as it is quite common for railway stations. I'll try to make a patch for it if you dont mind

[tordanik]

If you wish to build it, roof:shape=round support would be welcome. I assume that the tag will soon be "officially" documented anyway.

(And of course, should you decide that you need a service for models in obj or some other format after all, just contact me to discuss specifics.)