IfcTaskType定义可以指定在工作控件中使用的特定任务类型。
该类型属于IFC4中新增加的类型。
IfcTaskType提供可以指定的所有类型的任务。它是工作单元的引用定义，可以分解为（一系列）子任务。请注意，引用定义不能是工作流定义的一部分，即IfcTaskType实例定义引用流程的最抽象级别，而不依赖于其他引用流程。
IfcTaskType的用法定义了一个或多个IfcTask出现的参数。可以通过IfcTaskTypeEnum数据类型中枚举的属性集或IfcTaskType的explict属性来指定参数。任务出现（IfcTask实体）通过IfcRelDefinesByType关系链接到任务类型。
图显示了作为任务模板库一部分的任务类型的定义。请注意，在此示例中，任务类型进一步细分为定义任务时间（例如，持续时间）和/或任务序列的任务。
Attribute definitions
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| 10 | PredefinedType | IfcTaskTypeEnum | [1:1] | Identifies the predefined types of a task type from which the type required may be set. | X |
| 11 | WorkMethod | IfcLabel | [0:1] | The method of work used in carrying out a task. | X |
Formal Propositions
| Rule | Description |
|---|---|
| CorrectPredefinedType | The attribute ProcessType must be asserted when the value of PredefinedType is set to USERDEFINED. |
Inherited definitions from supertypes
Entity inheritance
Attribute inheritance
| # | Attribute | Type | Cardinality | Description | C |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | [1:1] | Assignment of a globally unique identifier within the entire software world. | X |
| 2 | OwnerHistory | IfcOwnerHistory | [0:1] | 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. |
X |
| 3 | Name | IfcLabel | [0:1] | 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 |
| 4 | Description | IfcText | [0:1] | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @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 | |
| Nests | IfcRelNests @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). | X | |
| IsNestedBy | IfcRelNests @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). | X | |
| HasContext | IfcRelDeclares @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. | X | |
| IsDecomposedBy | IfcRelAggregates @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). | X | |
| Decomposes | IfcRelAggregates @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). | X | |
| HasAssociations | IfcRelAssociates @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 | |
| IfcTypeObject | |||||
| 5 | ApplicableOccurrence | IfcIdentifier | [0:1] | The attribute optionally defines the data type of the occurrence object, to which the assigned type object can relate. If not present, no instruction is given to which occurrence object the type object is applicable. The following conventions are used:
EXAMPLE Refering to a furniture as applicable occurrence entity would be expressed as 'IfcFurnishingElement', refering to a brace as applicable entity would be expressed as 'IfcMember/BRACE', refering to a wall and wall standard case would be expressed as 'IfcWall, IfcWallStandardCase'. |
X |
| 6 | HasPropertySets | IfcPropertySetDefinition | S[1:?] | Set list of unique property sets, that are associated with the object type and are common to all object occurrences referring to this object type. | X |
| Types | IfcRelDefinesByType @RelatingType |
S[0:1] | Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type. | X | |
| IfcTypeProcess | |||||
| 7 | Identification | IfcIdentifier | [0:1] | An identifying designation given to a process type. | X |
| 8 | LongDescription | IfcText | [0:1] | An long description, or text, describing the activity in detail.
NOTE The inherited SELFIfcRoot.Description attribute is used as the short description. |
X |
| 9 | ProcessType | IfcLabel | [0:1] | The type denotes a particular type that indicates the process 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 |
| OperatesOn | IfcRelAssignsToProcess @RelatingProcess |
S[0:?] | Set of relationships to other objects, e.g. products, processes, controls, resources or actors that are operated on by the process type. | X | |
| IfcTaskType | |||||
| 10 | PredefinedType | IfcTaskTypeEnum | [1:1] | Identifies the predefined types of a task type from which the type required may be set. | X |
| 11 | WorkMethod | IfcLabel | [0:1] | The method of work used in carrying out a task. | X |
Definitions applying to Common Use Definitions
概念用法：
对象嵌套
对象嵌套概念适用于此实体。
IfcTaskType可以使用IfcRelNests关系嵌套其他IfcTaskType或IfcTask实体。这样的嵌套表示分解的细节级别。如果任务类型应按任务序列详细说明，或者如果需要包括额外的时间信息，例如子任务的持续时间，则使用IfcTask实体的嵌套。请注意，包含在IfcTaskType中的IfcTask实体通过IfcRelDefinesByObject关系与其任务发生链接。也可以通过IfcRelDefinesByType关系为这些IfcTask实体定义任务类型。有关详细信息，请参阅IfcRelDefinesByObject的文档。
概念继承
| # | Concept | Model View |
|---|---|---|
| IfcRoot | ||
| Software Identity | Common Use Definitions | |
| Revision Control | Common Use Definitions | |
| IfcTaskType | ||
| Object Nesting | Common Use Definitions | |