|To mark part of building, which has attributes, different from such ones at other parts|
|Used on these elements|
|Status: In use|
|Tools for this tag|
A way with the tag building:part=* describes a part of a building where some building attributes or the building function are different from the rest of the building.
How to use
Main article: Simple 3D buildings
Use building:part=yes for parts of the building which only have different attributes (building:levels=* and height=*). Use building:part=(type of building) for parts of the building which have a different function and possibly attributes (e.g. building:part=roof or building:part=retail).
In addition to the different ways tagged building:part=yes, there should be one area (closed way) marking the outline of the whole building, tagged with building=*. It is also recommended to use a type=building relation to group together the outline way and the building:part=yes ways.
Where a building has been split into parts, the whole building way should still have the tags building:levels=* and height=*. These values should be the maximum of all the building parts. A building that has a three-story part and a six-story part is still a six-story building.