IFC 4.3.x development

5.1.3.20 IfcQuantitySet

Change log

IFC4

added

5.1.3.20.1 Semantic definitions at the entity

IfcQuantitySet is the the abstract supertype for all quantity sets attached to objects. The quantity set is a container class that holds the individual quantities within a quantity tree. These quantities are interpreted according to their name attribute and classified according to their measure type. Some quantity sets are included in the IFC specification and have a predefined set of quantities indicated by assigning a significant name. These quantity sets are listed as "quantity sets" within this specification. Quantity sets applicable to certain objects are listed in the object specification.

An IfcPropertySetTemplate may define the underlying structure, i.e. the required name, the applicable object or object types to which the quantity set can be attached, and the individual quantities that maybe included. Quantity sets are related to other objects by using the relationship object that refers to the corresponding object:

  • Occurrence Object: IfcRelDefinesByProperties using the inverse attribute DefinesOccurrence.
  • Type Object: using a direct link by inverse attribute DefinesType.
  • Underlying template: IfcRelDefinesByTemplate using the inverse attribute IsDefinedBy.
  • External reference: subtypes of IfcRelAssociates are used to provide a link to a classification system, or external library providing further reference to the quantity set. Accessible by inverse attribute HasAssociations.

HISTORY  New entity in IFC4.

# Attribute Type Description
IfcRoot
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.
IfcPropertyDefinition
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions
HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects Reference to the relationship IfcRelAssociates and thus to those externally defined concepts, like classifications, documents, or library information, which are associated to the property definition.
IfcPropertySetDefinition
DefinesType SET [0:?] OF IfcTypeObject FOR HasPropertySets The type object to which the property set is assigned. The property set acts as a shared property set to all occurrences of the type object.

> NOTE  The relationship between the IfcPropertySetDefinition and the IfcTypeObject is a direct relationship, not utilizing IfcRelDefinesByProperties, for maintaining compatibility with earlier releases of this standard.

> IFC4 CHANGE  The cardinality has been changed from 0:1 to 0:? with upward compatibility for file based exchange.
IsDefinedBy SET [0:?] OF IfcRelDefinesByTemplate FOR RelatedPropertySets Relation to the property set template, via the objectified relationship IfcRelDefinesByTemplate, that, if given, provides the definition template for the property set or quantity set and its properties.

> IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
DefinesOccurrenceSET [0:?] OF IfcRelDefinesByProperties FOR RelatingPropertyDefinitionReference to the relation to one or many object occurrences that are characterized by the property set definition. A single property set can be assigned to multiple object occurrences using the objectified relationship IfcRefDefinesByProperties.

> IFC4 CHANGE Inverse attribute renamed from PropertyDefinitionOf with upward compatibility for file-based exchange.

5.1.3.20.1 Entity inheritance

dot_inheritance IfcElementQuantity IfcElementQuantity IfcQuantitySet IfcQuantitySet IfcElementQuantity->IfcQuantitySet IfcPropertySetDefinition IfcPropertySetDefinition IfcQuantitySet->IfcPropertySetDefinition IfcPreDefinedPropertySet IfcPreDefinedPropertySet IfcPreDefinedPropertySet->IfcPropertySetDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertySetDefinition->IfcPropertyDefinition IfcPropertySet IfcPropertySet IfcPropertySet->IfcPropertySetDefinition IfcPropertyTemplateDefinition IfcPropertyTemplateDefinition IfcPropertyTemplateDefinition->IfcPropertyDefinition IfcRoot IfcRoot IfcPropertyDefinition->IfcRoot IfcObjectDefinition IfcObjectDefinition IfcObjectDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

5.1.3.20.2 Definitions applying to General Usage

5.1.3.20.2.1 Identity

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

5.1.3.20.2.2 Revision Control

Ownership, history, and merge state is captured using IfcOwnerHistory.

5.1.3.20.3 Formal representations

ENTITY IfcQuantitySet
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcElementQuantity))
 SUBTYPE OF (IfcPropertySetDefinition);
END_ENTITY;