Type de tâche
Aufgabe - Typ

An IfcTaskType defines a particular type of task that may be specified for use within a work control.

HISTORY  New entity in IFC4

An IfcTaskType provides for all forms of types of task that may be specified. It is a reference definition for a unit of work that may be broken down into (a sequence of) subtasks. Please note that a reference definition can not be part of a workflow definition, i.e. IfcTaskType instances define the most abstract level of a reference process without dependencies to other reference processes.

Usage of IfcTaskType defines the parameters for one or more occurrences of IfcTask. Parameters may be specified through property sets that may be enumerated in the IfcTaskTypeEnum data type or through explict attributes of IfcTaskType. Task occurrences (IfcTask entities) are linked to the task type through the IfcRelDefinesByType relationship.

Figure 107 shows the definition of a task type that is part of a task template library. Please note that in this example the task type is further subdivided into tasks that define task times (for example, duration) and/or a task sequence.

task type instantiation diagram

Figure 107 — Task type relationships

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Object Nesting

The Object Nesting concept applies to this entity.

IfcTaskType may nest other IfcTaskType or IfcTask entities using the IfcRelNests relationship. Such nesting indicates decomposed level of detail. Nesting of IfcTask entities is used if a task type shall be detailed by a sequence of tasks or if there is a need to include additional time information such as the duration of subtasks. Please note that IfcTask entities being contained within an IfcTaskType are linked with their task occurrences via IfcRelDefinesByObject relationships. It is also possible to define a task type for these IfcTask entities via IfcRelDefinesByType relationships. For further information please see the documentation of IfcRelDefinesByObject.

XSD Specification:

 <xs:element name="IfcTaskType" type="ifc:IfcTaskType" substitutionGroup="ifc:IfcTypeProcess" nillable="true"/>
 <xs:complexType name="IfcTaskType">
   <xs:extension base="ifc:IfcTypeProcess">
    <xs:attribute name="PredefinedType" type="ifc:IfcTaskTypeEnum" use="optional"/>
    <xs:attribute name="WorkMethod" type="ifc:IfcLabel" use="optional"/>

EXPRESS Specification:

ENTITY IfcTaskType
SUBTYPE OF IfcTypeProcess;
PredefinedType : IfcTaskTypeEnum;
WorkMethod : OPTIONAL IfcLabel;
CorrectPredefinedType : (PredefinedType <> IfcTaskTypeEnum.USERDEFINED) OR ((PredefinedType = IfcTaskTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcTypeProcess.ProcessType)) ;

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

PredefinedType : Identifies the predefined types of a task type from which the type required may be set.
WorkMethod : The method of work used in carrying out a task.

Formal Propositions:

CorrectPredefinedType : The attribute ProcessType must be asserted when the value of PredefinedType is set to USERDEFINED.

Inheritance Graph:

ENTITY IfcTaskType
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
HasAssignments : SET OF IfcRelAssigns FOR RelatedObjects;
Nests : SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy : SET OF IfcRelNests FOR RelatingObject;
HasContext : SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy : SET OF IfcRelAggregates FOR RelatingObject;
Decomposes : SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations : SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcTypeObject
ApplicableOccurrence : OPTIONAL IfcIdentifier;
HasPropertySets : OPTIONAL SET [1:?] OF IfcPropertySetDefinition;
Types : SET [0:1] OF IfcRelDefinesByType FOR RelatingType;
ENTITY IfcTypeProcess
Identification : OPTIONAL IfcIdentifier;
LongDescription : OPTIONAL IfcText;
ProcessType : OPTIONAL IfcLabel;
OperatesOn : SET OF IfcRelAssignsToProcess FOR RelatingProcess;
ENTITY IfcTaskType
PredefinedType : IfcTaskTypeEnum;
WorkMethod : OPTIONAL IfcLabel;

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