Definition from ISO/CD 10303-46:1992: The layered things type
selects those things, which can be grouped in layers.
Definition from IAI: It is the collection of all those items,
that are assigned to a single layer. These items are representation items or
complete representations (IfcRepresentationItem, IfcRepresentation). If
an IfcRepresentation is referenced, all IfcRepresentationItem
within its set of Items are assigned to the same layer.
NOTE: Corresponding STEP name:
layered_item. It was called layered_things in the ISO/CD version and had been
renamed to layered_item in the ISO/IS final version. Please refer to ISO/IS
10303-46:1994, p. 13 for the final definition of the formal standard.
HISTORY: New type in Release
IFC2x 2nd Edition.
