There are several zone types:

Zone of this type represents a room inside a building and has all of the following elements:
- area element
- floor element
- wall elements
- ceiling element
- volume element
- opening elements (if any)
- label element(s)
It has all attributes listed in 'Attributes List' chapter except 'floors_count'.

Zone of this type roughly represents a whole building (for urban design purposes)
so it doesn't have any elements related to room only (floor, walls, ceiling and openings).
It has the following elements:
- area element
- volume element
- label element(s)
Zone of this type does not have room-related attributes obviously, but it has 'floors_count' attribute.

The most simple type. It has only the following elements:
- area element
- label element(s)
In contrast with previous type it doesn't even have height or volume. It might be used for urban design as well. It is possible to
represent some flat elements of a site plan using this type of a zone.
Extension treats zone objects without specified zone type attribute as zones of a 'room' type. It was made for
backward compatibility with previous version, in which zone type feature was not implemented yet.