Definition from buildingSMART International: An IfcClassificationReference is a
reference into a classification system or source (see
IfcClassification). An optional inherited ItemReference key is
also provided to allow more specific references to classification items (or
tables) by type. The inherited Name attribute allows for a human
interpretable designation of a classification notation (or code) - see use
definition of "Lightweight Classification".
HISTORY: New entity in IFC
The IfcClassificationReference can be used as a form of
'lightweight' classification through the 'ItemReference' attribute
inherited from the abstract IfcExternalReference class. In this case,
the 'ItemReference' could take (for instance) the Uniclass notation
"L6814" which, if the classification was well understood by all parties and was
known to be taken from a particular classification source, would be sufficient.
The Name attribute could be the title "Tanking". This would remove the
need for the overhead of the more complete classification structure of the
However, it is not recommended that this lightweight method be used in
cases where more than one classification system is in use or where there may be
uncertainty as to the origin or meaning of the classification.
Referencing from an External Source
Classifications of an object may be referenced from an external source
rather than being contained within the IFC model. This is done through the
|| The classification system or source that is referenced.