this tab allows to define which building will be built inside each created building lot.
there's 3 parts :

1 Available Categories : a building library can belong to one or several building categories. here one choose which category will be used to create the city.
2 Define the selected category : in this example the residential category is defined. each created lot is compared to the category definition. if the lot matches the definition, the lot will belong to the category.
3 Available Libraries. once the lot has been categorised, a building library within the category is chosen.
Available Categories
the available categories are displayed here : residential, house and industrial. this list can vary depending on the installed libraries.
each category can be enabled by pressing the corresponding On button. in this example, only the libraries that belong to the residential and the house categories are used.
by pressing the button with the category name, one displays the definition and the available libraries panels ( 2 and 3 ) of the category.
the R button allows to reload the libraries, in case you have just added a new one, or if you modified a parameter of an existing one, or if you want to reload the libraries default parameters.
Define the selected category
this part allows to categorize each lot in a building category.
when a lot doesn't match any category definition , it is then categorized in default.
the definition criterias vary depending on the used data sources.
zoning disabled:
when zoning is disabled, lots can be grouped per heights and per areas. these criterias will define the categories. here the residential category groups lots between 10 and 20 floors, whom area ranges between 10 and 20 meters (which is absurd, the interval should be min 500 and max 2500 for example).
when two or more categories have common criterias, a lot could match to several categories. in this case the category will be randomly chosen. the randomness is influenced by the slider in the the up-right corner : 1 gives more chances to the category to be selected, compared to another category with a value of 0.5.
zoning enabled :
when zoning is enabled, categories are defined by the zoning image pixel color at the lot location. in this case the category is defined by a color channel.
if several categories use the same color channel, the category is chosen randomly. as for the zoning disabled panel, the Chances of use slider allows to influence the choice.
Available Libraries
this part displays the available libraries in the selected category.
once the lot has been categorized, it will use one of the library listed and enabled here.
the little O button allows to enable or disable a library for this category. if a library belongs to several categories, it can be enabled in one category and disabled in another one.
each slider allows to influence the choice between the libraries. here the littleneo/residential library has almost all the chances to be selected compared to littleneo/cottage, for this category.
libraries can have limitations, for example the number of floors or the building area they can create. they are mor or less able to fit in a building lot. therefore they can have their own filters, defined by the library author, to limit the library use with some criterias (floors interval, area or side lenght filters..). these limitations also influence the library selection.
when zoning is enabled, the zoning and the elevation datas can conflict. it is solved by the Priority parameter of the zoning part of the Inputs tab.