Structures are the elements that forms the buildings blocks with energy zones. These are the walls, floors, ceilings, roofs, carriers (columns and beams) and openings like doors and glazing. Walls, floors, roofs and ceilings are the main structures of a building block and their shape cannot be edited, because it is based on the shape of the building block.
In ECO-engine a structure belongs to a building block with energy zones and are used to identify surfaces in the energy zones that contains the structure properties. Structures may belong to one or more spaces in a building block. For example part of a beam can be in two or more zones. This is automatically identified be ECO-engine, so the user can draw a structure as hole, without caring about in which space it belongs.