Definition from IAI: A physical quantity, IfcQuantityArea,
that defines a derived area measure to provide an element's physical property.
It is normally derived from the physical properties of the element under the
specific measure rules given by a method of measurement.
EXAMPLE: An opening may have an opening area
used to deduct it from the wall surface area. The actual size of the area
depends on the method of measurement used.
HISTORY New entity in IFC Release 2.x.
NOTE: It replaces the calcXxx attributes used in previous IFC
Releases
ISSUE See issue and change log for changes made in IFC Release
2.x