A generic and abstract relationship which subtypes are used to:
EXAMPLE Several instances of windows within the IFC project model may be of the same (catalogue or manufacturer) type. Thereby they share the same properties. This relationship is established by the subtype IfcRelDefinesByType of IfcRelDefines relationship assigning an IfcWindowStyle to multiple occurrences IfcWindow.
EXAMPLE The (same) property set, e.g. Pset_ProductManufacturerInfo, keeping the manufacturer name, label and production year of a product, can be assigned to one, or many instances of furnishing. This relationship is established by the subtype IfcRelDefinesByProperties of IfcRelDefines relationship assigning an IfcPropertySet to one or more instances of IfcFurnishingElement.
HISTORY New entity in IFC2x.
|1||GlobalId||IfcGloballyUniqueId||Assignment of a globally unique identifier within the entire software world.|
|2||OwnerHistory||OPTIONAL IfcOwnerHistory||Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, |
> NOTE only the last modification in stored - either as addition, deletion or modification.
> IFC4 CHANGE The attribute has been changed to be OPTIONAL.
|3||Name||OPTIONAL IfcLabel||Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.|
|4||Description||OPTIONAL IfcText||Optional description, provided for exchanging informative comments.|
IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Ownership, history, and merge state is captured using IfcOwnerHistory.
ENTITY IfcRelDefines ABSTRACT SUPERTYPE OF (ONEOF (IfcRelDefinesByObject ,IfcRelDefinesByProperties ,IfcRelDefinesByTemplate ,IfcRelDefinesByType)) SUBTYPE OF (IfcRelationship); END_ENTITY;