IFC 4.3.x development

5.3.3.1 IfcEvent

Change log

IFC4

added

5.3.3.1.1 Semantic definitions at the entity

An IfcEvent is something that happens that triggers an action or response.

HISTORY  New entity in IFC4

Use definitions

IfcEvent is used to capture information about particular things that happen or that may happen. Particularly used in work plans (or process maps) they identify e.g. a point at which a message containing information may be issued or at which a rule or constraint is invoked.

5.3.3.1.1 Attributes

# 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.
IfcObjectDefinition
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects 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.
Nests SET [0:1] OF IfcRelNests FOR RelatedObjects 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.
IsNestedBy SET [0:?] OF IfcRelNests FOR RelatingObject 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.
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions 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.
IsDecomposedBy SET [0:?] OF IfcRelAggregates FOR RelatingObject 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.
Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects 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.
HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects 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.
IfcObject
5 ObjectType OPTIONAL IfcLabel 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.
IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects 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.
Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject 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.
IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects 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.
IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjectsSet 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.
IfcProcess
6 Identification OPTIONAL IfcIdentifier An identifying designation given to a process or activity.

It is the identifier at the occurrence level.



> IFC4 CHANGE Attribute promoted from subtypes.
7 LongDescription OPTIONAL IfcText An extended description or narrative that may be provided.

> IFC4 CHANGE  New attribute.
IsPredecessorTo SET [0:?] OF IfcRelSequence FOR RelatingProcess Dependency between two activities, it refers to the subsequent activity for which this activity is the predecessor. The link between two activities can include a link type and a lag time.
IsSuccessorFrom SET [0:?] OF IfcRelSequence FOR RelatedProcess Dependency between two activities, it refers to the previous activity for which this activity is the successor. The link between two activities can include a link type and a lag time.
OperatesOn SET [0:?] OF IfcRelAssignsToProcess FOR RelatingProcess Set of relationships to other objects, e.g. products, processes, controls, resources or actors, that are operated on by the process.
IfcEvent
8 PredefinedType OPTIONAL IfcEventTypeEnum Identifies the predefined types of an event from which

the type required may be set.
9 EventTriggerType OPTIONAL IfcEventTriggerTypeEnum Identifies the predefined types of event trigger from which

the type required may be set.
10 UserDefinedEventTriggerTypeOPTIONAL IfcLabel A user defined event trigger type, the value of which is

asserted when the value of an event trigger type is declared

as USERDEFINED.
11 EventOccurenceTime OPTIONAL IfcEventTime The date and/or time at which an event occurs.

5.3.3.1.2 Entity inheritance

dot_inheritance IfcEvent IfcEvent IfcProcess IfcProcess IfcEvent->IfcProcess IfcProcedure IfcProcedure IfcProcedure->IfcProcess IfcObject IfcObject IfcProcess->IfcObject IfcTask IfcTask IfcTask->IfcProcess IfcObject_children 5 more... IfcObject_children->IfcObject IfcObjectDefinition IfcObjectDefinition IfcObject->IfcObjectDefinition IfcContext IfcContext IfcContext->IfcObjectDefinition IfcRoot IfcRoot IfcObjectDefinition->IfcRoot IfcTypeObject IfcTypeObject IfcTypeObject->IfcObjectDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertyDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

5.3.3.1.3 Definitions applying to General Usage

5.3.3.1.3.1 Classification Association

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

5.3.3.1.3.2 Control Assignment

An IfcEvent may be assigned to an IfcWorkCalendar to indicate times when such event is active using IfcRelAssignsToControl; otherwise the effective calendar is determined by the nearest IfcProcess ancestor with a calendar assigned.

5.3.3.1.3.3 Identity

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

5.3.3.1.3.4 Nesting

IfcEvent may be contained within an IfcTask using the IfcRelNests relationship. The event is considered active during the time period of the enclosing task (including any assigned IfcWorkCalendar); that is such event may be triggered within the task time period but not outside of it. As an IfcEvent is considered to be atomic, no use is anticipated for nesting processes inside the event.

5.3.3.1.3.5 Object Predefined Type

5.3.3.1.3.6 Object Typing

The IfcEvent defines the anticipated or actual occurrence of any event; common information about event types is handled by IfcEventType.

RelatingType
'IfcEventType'

5.3.3.1.3.7 Object User Identity

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as ifcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

5.3.3.1.3.8 Product Assignment

For building operation scenarios, IfcEvent may be assigned to a product (IfcElement subtype) using IfcRelAssignsToProduct to indicate a specific product occurrence that sources the event.

EXAMPLE  An IfcSensor for a motion sensor may have a "Motion Sensed" event. If the IfcEvent is defined by an IfcEventType and the IfcEventType is assigned to a product type (using IfcRelAssignsToProduct), then the IfcEvent must be assigned to one or more occurrences of the specified product type using IfcRelAssignsToProduct.

5.3.3.1.3.9 Property Sets

5.3.3.1.3.10 Property Sets for Objects

PsetName
'Pset_Risk'

5.3.3.1.3.11 Property Sets with Override

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case, that the same property (within the same property set, is defined both, in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

5.3.3.1.3.12 Revision Control

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

5.3.3.1.3.13 Sequential Connectivity

The relationship IfcRelSequence is used to indicate control flow. An IfcEvent as a predecessor (IfcRelSequence.RelatingProcess) indicates that the succeeding process (typically IfcProcedure or IfcTask) is triggered in response to the event. An IfcEvent as a successor (IfcRelSequence.RelatedProcess) indicates that the completion of the preceeding process causes the event to be triggered. As events have zero duration, the IfcRelSequence.SequenceType attribute has no effect on an IfcEvent but still applies to the opposite end of the relationship if IfcTask is used.

5.3.3.1.4 Formal representations

ENTITY IfcEvent
 SUBTYPE OF (IfcProcess);
	PredefinedType : OPTIONAL IfcEventTypeEnum;
	EventTriggerType : OPTIONAL IfcEventTriggerTypeEnum;
	UserDefinedEventTriggerType : OPTIONAL IfcLabel;
	EventOccurenceTime : OPTIONAL IfcEventTime;
 WHERE
	CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcEventTypeEnum.USERDEFINED) OR ((PredefinedType = IfcEventTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcObject.ObjectType));
	CorrectTypeAssigned : NOT(EXISTS(EventTriggerType)) OR (EventTriggerType <> IfcEventTriggerTypeEnum.USERDEFINED) OR ((EventTriggerType = IfcEventTriggerTypeEnum.USERDEFINED) AND EXISTS(UserDefinedEventTriggerType));
END_ENTITY;