#### 5.3.3.3 IfcTaskType

| 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 71 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.

Figure 71 — Task type relationships

## Electrical System Design

Instance diagram

Identity

The Identity concept applies to this entity.

Nesting

The 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.

Process Type Assignment

The Process Type Assignment concept applies to this entity as shown in Table 10.

Type | Description
--- | ---
IfcSubContractResourceType | An available rate structure for delivering the specified service type.
Table 10 — IfcTaskType Process Type Assignment

Exchange |  |  |  |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Import |  |  |  |  |  |  |  |  |  |  |  |  |
Export |  |  |  |  |  |  |  |  |  |  |  |  |

XSD Specification:

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

EXPRESS Specification:

ENTITY IfcTaskType

| SUBTYPE OF (IfcTypeProcess);

PredefinedType | : | IfcTaskTypeEnum;
WorkMethod | : | OPTIONAL IfcStrippedOptional;

| WHERE

CorrectPredefinedType | : | (PredefinedType <> IfcTaskTypeEnum.USERDEFINED) OR ((PredefinedType = IfcTaskTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcTypeProcess.ProcessType)) ;

END_ENTITY;

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

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcObjectDefinition

| INVERSE

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 IfcStrippedOptional;
HasPropertySets | : | OPTIONAL SET [1:?] OF IfcPropertySetDefinition;

| INVERSE

Types | : | SET [0:1] OF IfcRelDefinesByType FOR RelatingType;

| ENTITY IfcTypeProcess

Identification | : | OPTIONAL IfcStrippedOptional;
LongDescription | : | OPTIONAL IfcStrippedOptional;
ProcessType | : | OPTIONAL IfcStrippedOptional;

| INVERSE

OperatesOn | : | SET OF IfcRelAssignsToProcess FOR RelatingProcess;

| ENTITY IfcTaskType

PredefinedType | : | IfcTaskTypeEnum;
WorkMethod | : | OPTIONAL IfcStrippedOptional;

END_ENTITY;

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