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Address: http://www.iai-international.org/Model/documentation/R20/Online_Documents/Documents/IfcKernel.htm
Title: IFC R2.0 Final  •  Size: 152592  •  Last Modified: Wed, 01 Aug 2001 07:13:14 GMT

Specification for IfcKernel

Link to EXPRESS Definition

EXPRESS Definition

Link to EXPRESS-G Diagram

EXPRESS-G Diagram


Table of contents


Simple Types

  • No Simple Types defined in this Schema
  • Select Types

    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

    O IfcObjectWithPlacementSelect

    Enumerations

    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

    C IfcContainedOrReferencedEnum
    IfcContainmentEnum
    P IfcProxyEnum
    R IfcResourceConsumptionEnum
    S IfcSequenceEnum

    Class Definitions

    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

    A IfcActor
    C IfcControl
    E IfcExtensionPropertySet
    G IfcGroup
    L IfcLocalPlacement
    M IfcModelingAid
    O IfcObject
    P IfcProcess
    IfcProduct
    IfcProject
    IfcPropertyDefinition
    IfcPropertySet
    IfcProxy
    R IfcRelActsUpon
    IfcRelAssignsProperties
    IfcRelAssignsTypedProperties
    IfcRelContains
    IfcRelControls
    IfcRelGroups
    IfcRelNests
    IfcRelProcessOperatesOn
    IfcRelSequence
    IfcRelationship
    IfcResource
    IfcRoot

    Functions

  • No Functions defined in this Schema

  • Schema Semantic Definition

    The schema IfcKernel defines the most abstract part within the IFC architecture. It captures general constructs, that are basically founded by their different semantic meaning in common understanding of an object model, like object, property and relationship. Those are then specialized into non-AEC/FM specific constructs, like product, process, control and resource, which form the main entry points for the next level, the Core Extension layer.

    The IfcKernel utilizes the translation of the IFC Meta model into IFC object model specification. It handles the basic functionality, such as relative location of products in space, sequence of processes in time, or general purpose grouping and nesting mechanism. It also lays the foundation of extensibility of IFC model by providing type driven property definition and property definition extension.

    The specification of IfcKernel is not intended for independent implementation, however, all shared and domain models at lower levels within the IFC architecture are required to use the kernel definitions to root their definitions.

    HISTORY This schema is new in IFC Release 1.5


    Select IfcObjectWithPlacementSelect

    Link to EXPRESS Definition

    EXPRESS Definition

    Select Semantic Definition

    Definition from IAI: The IfcObjectWithPlacementSelect defines the three high level classes in IFC, that define their own placement. These objects can therefore provide the local (or in case of IfcProject -- global) coordinate system to which other object coordinate systems can refer.

    History

    This Select Type has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-212 and I-312 for changes made in IFC Release 1.5.

    Select

    IfcProduct

    IfcModelingAid

    IfcProject


    Type IfcContainedOrReferencedEnum

    Link to EXPRESS Definition

    EXPRESS Definition

    Type Semantic Definition

    Definition from IAI: This enumeration defines the whether the containment type is "Contained" or "Referenced". Contained means a hierarchical relationship between the contained item and the container, where any item can only be contained once. Referenced means a non-hierarchical relationship between the referenced item and the referencing container, where any item can be referenced by one or many referencing containers.

    The term "container" is used for any item in a logical structuring systems, to which an object is assigned to (either "Contained" or "Referenced"). A structuring system can be the project structure of site à building à building story à space, where each individual site, building, building story, or space object can act as an "container" for objects.

    EXAMPLE A multi-story space is contained (i.e. in hierarchic relationship) to the building story, on which its ground level is. The same multi-story space is referenced by any building story, through which it spans.

    History

    New Enumeration in IFC Release 2.0
    ISSUE See Issues I-114 and I-116 for changes made in IFC Release 1.5.

    Enumeration

    Contained

    Referenced


    Type IfcContainmentEnum

    Link to EXPRESS Definition

    EXPRESS Definition

    Type Semantic Definition

    Definition from IAI: This enumeration defines the different containment types, that further refine the containment relationship.

    History

    This Enumeration has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See Issues I-114 and I-116 for changes made in IFC Release 1.5.

    Enumeration

    ProjectContainer

    SiteContainer

    BuildingContainer

    BuildingStoreyContainer

    SpaceContainer

    ZoneContainer

    NotDefined


    Type IfcProxyEnum

    Link to EXPRESS Definition

    EXPRESS Definition

    Type Semantic Definition

    Definition from IAI: This enumeration defines the high level categorization of an IfcProxy. It indicates to which subtype of IfcObject the Proxy would otherwise comply.

    History

    This Enumeration has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-184 for changes made in IFC Release 1.5.

    Enumeration

    Product

    Process

    Control

    Document

    Resource

    NotDefined


    Type IfcResourceConsumptionEnum

    Link to EXPRESS Definition

    EXPRESS Definition

    Type Semantic Definition

    Definition from IAI: This enumeration indicates how the resource is consumed during the use.

    History

    New Enumeration in IFC Release 2.0
    ISSUE See issue I-487 for changes made in IFC Release 2.0.

    Enumeration

    Consumed

    PartiallyConsumed

    Occupied

    PartiallyOccupied

    NotOccupied

    UserDefined

    NotDefined


    Type IfcSequenceEnum

    Link to EXPRESS Definition

    EXPRESS Definition

    Type Semantic Definition

    Definition from IAI: : This enumeration defines the different ways, in which a time lag is applied to a sequence between two processes.

    History

    This Enumeration has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-200 for changes made in IFC Release 1.5.

    Enumeration

    Start_Start

    Start_Finish

    Finish_Start

    Finish_Finish

    NotDefined


    Class IfcActor

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcActor defines all actors or human agents involved in a project during its full life cycle. It facilitates the use of person and organization definitions in the resource part of the IFC object model.

    History

    New Class in IFC Release 2.0
    ISSUE See issues I-478, I-516 for changes made in IFC Release 2.0.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcActor
     IfcOccupant

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    TheActor

     

    IfcActorSelect

    Information about the actor

    INV

    IsActingUpon

     

    SET [0:?] OF IfcRelActsUpon

    Reference to the relationship that associates the actor to an object.


    Class IfcControl

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcControl is the abstract generalization of all concepts that control or constrain Products or Processes in general. It can be seen as a specification, regulation, constraint or other requirement applied to a product or process whose requirements and provisions must be fulfilled.

    Examples for Controls are space program, construction guides, etc. It is defined in the Kernel but will be reused and specialized in other schemas.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-094 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcControl
     IfcConnectionGeometry
     IfcSpaceProgram
     IfcFurnitureModel
     IfcOccupancySchedule
     IfcScheduleTimeControl
     IfcWorkPlan
     IfcProjectOrder
     IfcDistributionPortGeometry
     IfcConstraint
     IfcCMDocPackage
     IfcOccupancyScheduleElement
     IfcWorkScheduleElement
     IfcWorkSchedule
     IfcCostElement
     IfcCostSchedule
     IfcApproval
     IfcMaintenanceRecord
     IfcMaintenanceType

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    Classification

     

    IfcClassificationList

    Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it.

    INV

    Controls

     

    SET [0:?] OF IfcRelControls

    Reference to the relationship that associates the control to the object(s) being controled.


    Class IfcExtensionPropertySet

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: Defines those dynamically extendable properties that are defined as extensions to the IFC Object model (see semantic definition of IfcObject). Extension property sets can form part of a regional flavor of IFC or can be project specific extensions to the actual content of an IFC release. The definition source (the body that defined the extension) has to be given.

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcPropertyDefinition
     IfcPropertySet
     IfcExtensionPropertySet

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    DefinitionSource

     

    STRING

    The Source attribute specifies the source of the external definition. It can be either the name of a recognised country or region, which defines a national flavour of IFC, or the name of a project consortium, or the name of a group of implementers.


    Class IfcGroup

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The generalization of any arbitrary group. A group is an aggregation of objects, which do not have any particular positioning relationship. Therefore a group is an aggregation under some non-geometrical/topological grouping aspects. An example for a group is the system, since it groups elements under the aspect of their role, regardless of their position in a building. A group can hold an aggregation of products, processes or other groups. Groups can therefore be nested.

    The GroupPurpose attribute may assign a descriptor, that defines the purpose of the group. As an example, a complex of buildings will be generated by assigning the individual buildings through the IfcRelGroups relationship to an IfcGroup, which is further specified by the GroupPurpose descriptor "BuildingComplex". Similarly the site complex is handled by an IfcGroup with the GroupPurpose descriptor "SiteComplex".

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-088 and I-213 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcGroup
     IfcSystem
     IfcZone
     IfcSpaceProgramGroup
     IfcInventory

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    GroupPurpose

     

    STRING

    Description of the Purpose behind grouping.

    INV

    IsGroupedBy

     

    IfcRelGroups

    Contains the relationship that assigns the group members to the group object.


    Class IfcLocalPlacement

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The relative placement between two products. It defines that the related object is placed within the local coordinate system of the relating object. Rules to prevent cyclic relative placements have to be introduced on the application level.

    The following conventions shall apply, if relative placement is used:

    If the PlacementRelTo Relationship is not given, then it defaults to an absolute placement within the WCS, i.e. relative to the IfcProject.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-212, I-255, I-260 and I-270 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcModelingAid
     IfcLocalPlacement
     IfcConstrainedPlacement

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    PlacementRelTo

     

    IfcObjectWithPlacementSelect

    Reference to Object that provides the relative placement by its local coordinate system, if it is omitted, then the Local Placement is given to the WCS, established by the IfcProject.

     

    RelativePlacement

     

    IfcAxis2Placement

    Geometric placement that defines the transformation from the related coordinate system into the relating. The placement can be either 2D or 3D, depending on the dimension count of the coordinate system.

    Formal Propositions

    WR31

    Either PlacementRelTo is not given, or it shall not refer to an IfcLocalPlacement directly.

    (NOT(EXISTS(PlacementRelTo))) OR (NOT('IFCKERNEL.IFCLOCALPLACEMENT' IN TYPEOF(PlacementRelTo)))


    Class IfcModelingAid

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: An IfcModelingAid provides the general concept for constructs that support the creation of design artifact, in particular its geometric form. They are part of the project information set, but not part of the artifact itself. Most common example of a modeling aid are the local placement and the design grid. Both provide aid to place Products into the design space. The grid supports in addition the definition of elements' constraint location and sometimes form, but the grid is not part of the constructed building.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-254 and I-255 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcModelingAid
     IfcLocalPlacement
     IfcDesignGrid
     IfcGridAxis
     IfcGridIntersection
     IfcGridLevel
     IfcPlacementConstraint
     IfcReferenceGeometryAid
     IfcLightSource
     IfcPhotometricOutputSpace

    Attributes and Relationships

    No attributes defined on this level.

    Class IfcObject

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The generalization of any semantically treated things and processes within IFC. Examples of IfcObject include physically tangible items, such as wall, beam or covering, physically existing items, such as spaces, or conceptual items, such as grids or virtual boundaries. It also stands for processes, such as work tasks, as well as for controls, etc.

    Objects are independent pieces of information that might contain or reference other pieces of information, most notably properties. Properties of objects can be of either of the following types:

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcControl
     IfcGroup
     IfcProcess
     IfcProduct
     IfcProject
     IfcProxy
     IfcResource
     IfcActor

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    UserDefinedType

     

    STRING

    User defined type, given for the instantiable subtypes of IfcObject. If for a given subtype, a predefined type exists (an attribute PredefinedType with the data type Enumaration, then the value for user defined is only valid, if the predefined value is set to UserDefined. Allows for the addition of regional extensions of IFC.

     

    DocumentReferences

     

    SET [0:?] OF IfcDocumentReference

    Reference to a document reference that holds the access information to an externally provided document.

    INV

    PartOfGroups

     

    SET [0:?] OF IfcRelGroups

    References to the grouping relationships, which allows the object to be part of many groups

    INV

    Nests

     

    SET [0:1] OF IfcRelNests

    Reference to the nesting relationship, that allows this object to be the nest of other nested objects

    INV

    IsNestedBy

     

    SET [0:?] OF IfcRelNests

    References to the nesting relationship, that allows this object to be nested within other objects

    INV

    Contains

     

    SET [0:2] OF IfcRelContains

    Set of Relationships to other Objects that are contained by this object.

    INV

    IsContainedBy

     

    SET [0:?] OF IfcRelContains

    Set of Relationships to other Objects in which this object is contained.

    INV

    OperatedInProcesses

     

    SET [0:?] OF IfcRelProcessOperatesOn

    Set of Relationships to processes which operated on the object.

    INV

    IsDefinedBy

     

    SET [0:?] OF IfcRelAssignsProperties

    Set of Relationships to properties (statically or dynamically defined) that further define the object..

    INV

    IsActedUpon

     

    SET [0:?] OF IfcRelActsUpon

    Set of Relationships to actors which acts upon the object.

    INV

    IsControlledBy

     

    SET [0:?] OF IfcRelControls

    Set of Relationships to controls which apply a control to the object.


    Class IfcProcess

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: An action taking place in building construction with the intent of acquiring or constructing products. Processes are placed in sequence (including overlapping for parallel tasks) in time.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-200, I-201 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcProcess
     IfcWorkTask
     IfcOccupancyTask

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    Productivity

     

    IfcMeasureWithUnit

    Productivity of the process (such as m³ per hour)

    OPT

    Classification

     

    IfcClassificationList

    Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it.

    INV

    IsSuccessorFrom

     

    SET [0:?] OF IfcRelSequence

    Relative placement in time, refers to the previous processes for which this process is successor.

    INV

    IsPredecessorTo

     

    SET [0:?] OF IfcRelSequence

    Relative placement in time, refers to the previous processes for which this process is predecessor.

    INV

    OperatesOn

     

    SET [0:?] OF IfcRelProcessOperatesOn

    Set of Relationships to objects that are operated on by the process


    Class IfcProduct

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: Any object, manufactured, supplied or created for incorporation into an AEC/FM project. This also includes objects that are created indirectly by other products, as spaces are defined by bounding elements. Products can be designated for permanent use or temporary use, an example for the latter is formwork.

    Products are defined by their properties and representations. Products occur at a specific location in space. They can be placed relatively to other products, but ultimately relative to the world coordinate system defined for this project.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcProduct
     IfcBuilding
     IfcBuildingStorey
     IfcElement
     IfcSite
     IfcSpatialElement
     IfcConstructionZoneAggregationProduct

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    LocalPlacement

     

    IfcLocalPlacement

    Contained relative placement in space, refers to the product that provides the local coordinate system for the Relative Placement and includes the transformation for the object coordinate system.

     

    Representations

     

    SET [0:2] OF IfcProductRepresentation

    Reference to the representations of the product, being either geometric shape representations or topological representations, or both. The product definition shape provides for multiple representations of the shape property of the object. The product definition topology provides for basic topology and connectivity information.

    OPT

    Classification

     

    IfcClassificationList

    Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it.


    Class IfcProject

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The undertaking of some engineering activities leading towards a product. It acts as the top container for all objects defining a project. The Project also holds the units used for certain measures throughout the project and the central registry, currently only for team members, applications and materials. The IfcProject establishes the World Coordinate System, WCS.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues I-084, I-001, I-003 for changes made in IFC Release 1.5.
    See issues I-298, I-328 for changes made in IFC Release 1.5.1.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcProject

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    OPT

    ReferenceName

     

    STRING

    Short name for the project as used for reference purposes.

    OPT

    Name

     

    STRING

    Long name for the project.

    OPT

    Phase

     

    STRING

    Current project phase, open to interpretation for all project partner, therefore given as IfcString.

     

    UnitsInContext

     

    IfcUnitAssignment

    Defines the units of measure that will be referred by defined data types in the attribute values of all attributes and properties of objects and relationships, defined in the context of this project.

    OPT

    Classification

     

    IfcClassificationList

    Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it.

     

    AbsolutePlacement

     

    IfcAxis2Placement

    Establishment of the World Coordinate System for the Project


    Class IfcPropertyDefinition

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: Defines the generalization of all properties (dynamically defined and statically defined). It cannot be instantiated as it is an ABSTRACT class.

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcPropertyDefinition
     IfcOccupancyNumber
     IfcSpaceUseCase
     IfcManufactureInformation
     IfcPropertySet
     IfcMetricValue
     IfcElectricalCharacteristics

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

    INV

    DefinitionOf

     

    IfcRelAssignsProperties

    Reference to the relation to one or many objects that are characterized by the property definition.


    Class IfcPropertySet

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: Defines all dynamically extendable properties (see semantic definition of IfcObject). The IfcPropertySet is a container class that allows the definition of collections of IfcProperty, and the nesting of other IfcPropertySet.

    History

    New Class in IFC Release 2.0
    ISSUES: See issues I-078, I-080, I-187, GI-003 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcPropertyDefinition
     IfcPropertySet
     IfcExtensionPropertySet

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    Name

     

    STRING

    Name of the property set as used within the project. The attribute is used to dynamically specify the type of the property definition. Directly instantiated at IfcPropertySet it provides for the properties defined as part of the IFC Object model (see semantic definition at IfcObject). The property set structure for that IfcPropertySet is given within the property set definition part of the IFC specification.

     

    HasProperties

     

    LIST [1:?] OF IfcProperty

    Contained list of properties. For property sets defined as part of the IFC Object model, the property objects within a property set are defined as part of the standard. If a property is not contained within the list of predefined properties, ist value has not been set at this time.


    Class IfcProxy

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcProxy is intended to be a kind of a container for wrapping up non-IFC objects for use within the persistent store. Given that we have only a limited number of constructs formally defined within IFC (and will never be able to define them all), we must provide a mechanism for capturing constructs (primarily geometric) that are not defined by IFC. These constructs may or may not have semantic meaning, depending on whether any representations or extended property sets are attached to the IfcProxy. Either way, a receiving system only has to ensure that they are maintained as part of the project model. Such a mechanism allows to exchange data that is part of the project but not necessarily part of the IFC model.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-184 for changes made in IFC Release 1.5.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcObject
     IfcProxy

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    ProxyType

     

    IfcProxyEnum

    High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process.

    OPT

    LocalPlacement

     

    IfcLocalPlacement

    In case of a Product Proxy, the placement within the space of the Project is given.

     

    Representations

     

    SET [0:2] OF IfcProductRepresentation

    In case of a Product Proxy, reference to the representations of the product, being either geometric shape representations or topological representations, or both. The product definition shape provides for multiple representations of the shape property of the object. The product definition topology provides for basic topology and connectivity information.

    Formal Propositions

    WR2

    Either the proxy is a product, or it should not have geometric or topologic representations.

    (ProxyType = Product) XOR ((ProxyType <> Product) AND (SIZEOF(Representations)=0))

    WR33

    If the IfcProxy is a Product, then a local placement shall be given, otherwise no local placement shall be given.

    ((ProxyType = Product) AND (EXISTS(LocalPlacement))) XOR ((ProxyType <> Product) AND NOT(EXISTS(LocalPlacement)))


    Class IfcRelActsUpon

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcRelActsUpon objectified relationship defines a relationship between an actor and one or many objects. An particular role of the actor played in that relationship can be associated.

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelActsUpon
     IfcRelOccupiesSpaces

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingActor

     

    IfcActor

    Reference to the actor.

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    Reference to the objects (or single object) on which the actor acts upon in a certain role (if given)

    OPT

    ActingRole

     

    IfcActorRole

    Role of the actor played within the assignment to the object(s).

    Formal Propositions

    WR32

    The relationship shall not define an actor to actor relationship.

    SIZEOF(QUERY(Temp <* RelatedObjects | 'IFCKERNEL.IFCACTOR' IN TYPEOF(Temp))) = 0

    Informal Propositions

    IP31

    The relationship shall be defined acyclic.


    Class IfcRelAssignsProperties

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcRelAssignsProperties class defines the light-weight relationships between properties and objects. Directly instantiated it provides for non-type driven property assignments (see semantic definition of IfcObject).

    The IfcRelAssignsProperties is a N:M relationship, as it allows for the assignment of one to many (related) properties to a single or many objects.

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelAssignsProperties
     IfcRelAssignsTypedProperties

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingPropertyDefinition

     

    IfcPropertyDefinition

    Reference to the property definition for that object or list of objects.

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    Reference to the objects (or single object) to which the property definition applies.

    OPT

    DomainView

     

    STRING

    The attribute DomainView optionally defines the domain, to which the assigned IfcPropertyDefinition relates. If not present, the IfcPropertyDefinition is applicable to all domain views. The DomainView is given as STRING type to allow an easy upgrade for new releases and for assigning arbitrary domain view names for externally defined property sets.

    DER

    IsShared

     

    LOGICAL

    The attribute IsShared reflects whether the property is assigned to a single object instance (FALSE = occurrence property,) or assigned to multiple object instances (TRUE = shared property, see semantic definition at IfcObject).


    Class IfcRelAssignsTypedProperties

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The IfcRelAssignsTypedProperties class defines the light-weight relationships between properties and objects for type-driven property assignments (see semantic definition of IfcObject). It is provided as specialization of IfcRelAssignsProperties.

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelAssignsProperties
     IfcRelAssignsTypedProperties

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    Name

     

    STRING

    The attributes Name defines the Name of the 'type' being defined, as given by the IFC specification. A 'type' is used to establish a standard of object property definitions, that may be used many times in a project. A given 'type' drives the assignment of one IfcPropertyDefinition instance (which might include other IfcPropertyDefinitions in case of nested property sets) to an IfcObject instance (occurrence type) or to many IfcObject instances (shared type).

    OPT

    TypedClass

     

    STRING

    The attribute TypedClass optionally defines the IfcObject, to which the assigned IfcPropertyDefinition relates. If not present, no instruction is given to which IfcObject the IfcPropertyDefinition is applicable.


    Class IfcRelContains

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: This objectified relationship handles the general concept of containment, that can be either realized by reference or by value. Currently the concept of containment is used for buildings as a special kind of AEC/FM products.

    A distinctions is made between the containment and the reference of Elements. A containment relationship shall lead to a hierarchical relationship, i.e. each element can only be contained by one instance of a element container (i.e. site, building, building storey, zone or space). It might however be referenced by many element containers. A multi-storey space is contained (or belongs to) the building storey at which its ground level is, but it is referenced by all the other building storeys, in which it spans. A lift shaft might be contained by the basement, but referenced by all storeys, through which it spans.

    A reference relationship provides for non-hierarchical relationships.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issues GI-008, I-116 for changes made in IFC Release 1.5.
    See issue I-310 for changes made in IFC Release 1.5.1.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelContains

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingObject

     

    IfcObject

    Reference to the container object

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    Reference to the contained objects

     

    RelationshipType

     

    IfcContainmentEnum

    Defines the type of relationship from the relating side, i.e. following the container object, in which the other objects are contained.

     

    ContainedOrReferenced

     

    IfcContainedOrReferencedEnum

    Defines whether the relationship is a hierarchical containment relationship (Contained) or a reference relationship (Referenced)

    Formal Propositions

    WR31

    The instance to which the RelatingObject relation points (container) shall not be contained in the List of RelatedObjects.

    SIZEOF(QUERY(Temp <* RelatedObjects | RelatingObject :=: Temp)) = 0

    Informal Propositions

    IP31

    The IfcRelContains relationship shall be defined acyclic.


    Class IfcRelControls

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: This objectified relationship handles the assignment of controls (subtypes of IfcControl) to other objects (subtypes of IfcObject, with the exception of controls).

    History

    New Class in IFC Release 2.0

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelControls
     IfcRelRelatesConstraints
     IfcRelCostsObjects
     IfcRelAssignsApprovals
     IfcRelControlsMaintenance

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingControl

     

    IfcControl

    Reference to the control that applies an control about objects.

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    Reference to the objects being controled.

    Formal Propositions

    WR31

    Control shall not be applied to control objects.

    SIZEOF (QUERY (temp <* RelatedObjects | 'IFCKERNEL.IFCCONTROL' IN TYPEOF(temp))) = 0

    Informal Propositions

    IP31

    The IfcRelControls relationship shall be defined acyclic.


    Class IfcRelGroups

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: This objectified relationship handles the assignment of group members to group objects. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type IfcGroup.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-310 for changes made in IFC Release 1.5.1.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelGroups

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingGroup

     

    IfcGroup

    Reference to group that finally contains all assigned group members.

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    References to Objects that will be contained in the group.

    Formal Propositions

    WR31

    The instance to with the relation points shall not be contained in the List of RelatedObjects.

    SIZEOF(QUERY(Temp <* RelatedObjects | RelatingGroup :=: Temp)) = 0

    WR32

    The dependency flags shall be set so that the RelatedObjects always depend on the RelatingObject (the group)

    (SELF\IfcRelationship.RelatedIsDependent = TRUE) AND (SELF\IfcRelationship.RelatingIsDependent = FALSE)


    Class IfcRelNests

    Link to the Fully Attributed View

    Fully Attributed View

    Link to EXPRESS Definition

    EXPRESS Definition

    Class Semantic Definition

    Definition from IAI: The nesting relationship defines the general concept of elements being nested, so that the nest is of the same type (or supertype) as the nested elements. An example is, that a cost element is a nest of other cost elements. The nesting relationship can be applied in a recursive manner.

    History

    This Class has changed after IFC Release 1.5.1, please see the Migration Guide for details
    ISSUE See issue I-310 for changes made in IFC Release 1.5.1.

    Attribute and Relationship Definitions

    Superclasses and Subclasses

     IfcRoot
     IfcRelationship
     IfcRelNests
     IfcRelNestsProcesses
     IfcRelNestsOccupancyScheduleElements
     IfcRelNestsOccupancySchedules
     IfcRelNestsWorkScheduleElements
     IfcRelNestsWorkSchedules
     IfcRelNestsCostElements
     IfcRelNestsCostSchedules

    Attributes and Relationships

    Attribute type (OPT, DER, INV)

    Redefinition (SELF)

    Attribute / Relation

    Data or Rel. type

    Definition

     

    RelatingObject

     

    IfcObject

    The object that represents the nest.

     

    RelatedObjects

     

    LIST [1:?] OF IfcObject

    The objects being nested.

    OPT

    NestingPurpose

     

    STRING

    Any description to explain the criteria about nesting those objects

    Formal Propositions

    WR31

    The instance to which the relation RelatingObject points shall not be contained in the List of RelatedObjects.

    SIZEOF(QUERY(Temp <* RelatedObjects | RelatingObject :=: Temp)) = 0

    WR32

    The type of the RelatingObject shall always be included in the type of each RelatedObject, i