IfcSystem

Natural language names
System (allgemein)
System
Système
Change log
ItemSPFXMLChangeDescription
IFC2x3 to IFC4
    IfcSystem
      OwnerHistoryMODIFIEDInstantiation changed to OPTIONAL.
Semantic definitions at the entity
Entity definition

A system is an organized combination of related parts within an AEC product, composed for a common purpose or function or to provide a service. A system is essentially a functionally related aggregation of products. The grouping relationship to one or several instances of IfcProduct (the system members) is handled by IfcRelAssignsToGroup.

NOTE  The use of IfcSystem often applies to the representation of building services related systems, such as the piping system, cold water system, etc. Members within such a system may or may not be connected using the connectivity related entities (through IfcDistributionPort).
HISTORY  New entity in IFC1.0
Attribute definitions
#AttributeTypeCardinalityDescription G
ServicesBuildingsIfcRelServicesBuildings
@RelatingSystem
S[0:1]Reference to the building spatial structure via the objectified relationship IfcRelServicesBuildings, which is serviced by the system. X
Inherited definitions from supertypes
Entity inheritance IfcBuildingSystem IfcDistributionSystem IfcStructuralAnalysisModel IfcZone IfcGroup IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRoot
1GlobalIdIfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory? 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.
X
3NameIfcLabel? 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. X
4DescriptionIfcText? Optional description, provided for exchanging informative comments.X
IfcObjectDefinition
HasAssignmentsIfcRelAssigns
@RelatedObjects
S[0:?]Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.X
NestsIfcRelNests
@RelatedObjects
S[0:1]References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.
X
IsNestedByIfcRelNests
@RelatingObject
S[0:?]References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.
X
HasContextIfcRelDeclares
@RelatedDefinitions
S[0:1]References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.
IFC4 CHANGE  The inverse attribute datatype has been added.
X
IsDecomposedByIfcRelAggregates
@RelatingObject
S[0:?]References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
DecomposesIfcRelAggregates
@RelatedObjects
S[0:1]References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
HasAssociationsIfcRelAssociates
@RelatedObjects
S[0:?]Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.X
IfcObject
5ObjectTypeIfcLabel? The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.
X
IsDeclaredByIfcRelDefinesByObject
@RelatedObjects
S[0:1]Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
X
DeclaresIfcRelDefinesByObject
@RelatingObject
S[0:?]Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
X
IsTypedByIfcRelDefinesByType
@RelatedObjects
S[0:1]Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.
IFC4 CHANGE  New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange.
X
IsDefinedByIfcRelDefinesByProperties
@RelatedObjects
S[0:?]Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.
IFC4 CHANGE  The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.
X
IfcGroup
IsGroupedByIfcRelAssignsToGroup
@RelatingGroup
S[0:?]Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.
IFC4 CHANGE  The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of IfcRelAssignsToGroup to assign the group members. The change has been done with upward compatibility for file based exchange.
X
IfcSystem
ServicesBuildingsIfcRelServicesBuildings
@RelatingSystem
S[0:1]Reference to the building spatial structure via the objectified relationship IfcRelServicesBuildings, which is serviced by the system. X
Definitions applying to General Usage

 Instance diagram


Concept usage

Property Sets

The Property Sets for Objects concept template applies to this entity as shown in Table 88.

PsetNameProperties
Pset_ServiceLifeFactors
TemplatePropertyNameUpperValueLowerValueSetValue
Bounded ValueQualityOfComponentsIfcPositiveRatioMeasure
Bounded ValueDesignLevelIfcPositiveRatioMeasure
Bounded ValueWorkExecutionLevelIfcPositiveRatioMeasure
Bounded ValueIndoorEnvironmentIfcPositiveRatioMeasure
Bounded ValueOutdoorEnvironmentIfcPositiveRatioMeasure
Bounded ValueInUseConditionsIfcPositiveRatioMeasure
Bounded ValueMaintenanceLevelIfcPositiveRatioMeasure

Table 88 — IfcSystem Property Sets for Objects



mvdXML Specification
<?xml version="1.0"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="ad7fcf5e-8155-4818-826e-62295c4ba574" name="IfcSystem" status="sample" applicableRootEntity="IfcSystem">
  <Applicability uuid="00000000-0000-0000-0000-000000000000" status="sample">
    <Template ref="92e6801c-da2d-48f3-aafa-ca7292ecd3a0" />
    <TemplateRules operator="and" />
  </Applicability>
  <Concepts>
    <Concept uuid="4879adbf-a42d-4155-b9e9-c4063dcc6d75" name="Property Sets" status="sample" override="false">
      <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
      <TemplateRules operator="and">
        <TemplateRule Parameters="PsetName[Value]='Pset_ServiceLifeFactors'" />
      </TemplateRules>
    </Concept>
  </Concepts>
</ConceptRoot>
Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
IfcObjectDefinition
Classification AssociationClassification AssociationGeneral Usage
IfcObject
Object User IdentityObject User IdentityGeneral Usage
Object Predefined TypeObject Predefined TypeGeneral Usage
Object TypingObject TypingGeneral Usage
Property Sets with OverrideProperty Sets with OverrideGeneral Usage
IfcGroup
Group AssignmentGroup AssignmentGeneral Usage
IfcSystem
Property SetsProperty Sets for ObjectsGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcSystem" type="ifc:IfcSystem" substitutionGroup="ifc:IfcGroup" nillable="true"/>
 <xs:complexType name="IfcSystem">
  <xs:complexContent>
   <xs:extension base="ifc:IfcGroup"/>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcSystem
 SUPERTYPE OF(ONEOF(IfcBuildingSystem, IfcDistributionSystem, IfcStructuralAnalysisModel, IfcZone))
 SUBTYPE OF (IfcGroup);
 INVERSE
  ServicesBuildings : SET [0:1] OF IfcRelServicesBuildings FOR RelatingSystem;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

References  References: IfcRelServicesBuildings

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