I think that your example is not really the best, white stripes are not the same shape as black glass one (they are a bit wider from top view).
The real question is “how to map a vertically repeated building:part”, i would suggest something inspired from the balconies repetition proposal.
Your example could be mapped as a single squared building part with total height for the central blue/black glass plus a single larger square with balconies inspired tags something like:
I think that negative values for roof:height don’t make sense, based on the definition of the key. A V-shaped roof still has a positive height (and would probably not be called “gabled” in English).
I don’t think we should even bring up “vertically repeated building parts” for this topic. In my opinion, colour patterns would ideally be represented just that: Tagging the type of pattern (vertical/horizontal/diagonal stripes, checkers, dots, whatever), the list of colours involved, and some additional parameters such as stripe width. If necessary, some of these parameters might be treated as lists, too - similar to the lanes syntax - but we should make sure to not go overboard with tagging complexity.
Enabling colour patterns – or even material patterns? – would be rather powerful and applicable beyond just buildings. What about a bollard with diagonal red-white stripes, for example? I wouldn’t want to introduce bollard:parts for that, but a colour pattern tagging could be applied to that, too - and all 3D objects where we can implement tagging-based colours.
I think that the coloring of the facade can be solved using Relations.
Relation type=facade, separately for each section of the perimeter of the building (front, rear, left side, right side.)
For a building in the shape of a polygon, we would specify the location of the section (part of the building), viewed from the centers and use the tag “direction =”.
Items of the Relation: facade:a; facade:b; etc.
height=
min_height=
colour=
width=
material=
and other specific tags for each level of color individually.
Hello Andreas,
Tri tower Ilmenau is absolotely ok, because of different Ground floor geometry in repetead levels.
Communication Tower with 3 or 4 stripes could also be ok.
But what about cases with 40 or more stripes?
Exactly,
but WHY do yo define new names, not compatible with common simple 3d building definition.
Don´t understand me wrong:
I´m really happy about your great job.
But: there are already names in use.
Mathematicly is butterfly roof the same as gabled but with negative value for the roof hight.
Because the code must know what to do with roof:shape=gabled and roof:shape=butterfly when height tag is not present.
With different roof:shape value you can deduce the result without looking at the roof:height tag.
I usually tag it with building:facade:material=glass & building:facade:colour=brown i’m not sure it’s the best way but it gives the best rendering in Kendzy & F4Map