Currently we can offer a level of detail grade 1 (LOD1) that extrudes 2D shapes to simple block models. LOD2 includes a detailed shape of the outer elements of a object, LOD3 is a perfect shape even with textures.
Objects are buildings but of course every other POI (monuments,....). This might cover procedural models, too (e.g. repeating/adapting a road segment or a tree to become a forest).
Feel free to expand the page. For personal comments let's use the talk page, please!
Internal Tagging
Most simple solution to tag and modell complex figures using OSM primitives as ways and special attributes that indicate
starting from ground
height
Some suggested but not widely used tags can indicate:
type of building
roof type
colours
Pros:
software tools already exist, mappers are familar with this process
Cons:
might result in complex splitted up 2D shapes and a huge amount of tags per object
problems with other renderers
mappers might get annoyed
no native approach on model in 3D
no generalisation possible (a normal block in east Germany looks like this...)
very limited details due to shape->extrude approach
nothing keeps the parts of a model together
tagging mostly for buildings won't affect to general POI models
no direct storage of textures
get heavy for OSM infrastructure
New API Revision
The OSM API is changing over time, we might introduce a new feature to API 0.7:
The 3D features could be hidden from users in "2D mode"
Pros:
Deeply integrated with OSM, no other dependant tool
can start from scratch -> define tools, formats, APIs on the usecase
can beneficiate of the OSM knowledge / infrastructure
Cons
need lot of work, in server & client
can be havy for OSM infrastructure?
very confusing structures in the editors
External DB
This might be an external related project storing the models.
Pros:
user can contribute without knowledge on OSM in general
can start from scratch -> define tools, formats, APIs on the usecase
can be used by others beside OSM
Cons
a lot of work todo (sep. platform)
spatial Organisation
To deal with this mass of datas, we need to use a vector tile approach.
Data format
Storing/Exchanging 3D Models needs a format with the following requirements:
able to store 3D geometry, textures, lights
This would be great, too:
altering parameters (e.g. switch light on at nights) and model (e.g. random small houses for allotments)
general coordinatesystem (indicating directions to next road, footway, coast,...)
