IFC 4.3.x development

5.3.3.7 IfcTaskType

Change log

5.3.3.7.1 Semantic definitions at the entity

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 1 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.

5.3.3.7.1 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.
IfcTypeObject
5	ApplicableOccurrence	OPTIONAL IfcIdentifier	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: * The IFC entity name of the applicable occurrence using the IFC naming convention, CamelCase with IFC prefix * It can be optionally followed by the predefined type after the separator "/" (forward slash), using uppercase * If one type object is applicable to many occurrence objects, then those occurrence object names should be separate by comma "," forming a comma separated string. > 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'.
6	HasPropertySets	OPTIONAL SET [1:?] OF IfcPropertySetDefinition	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. > IFC2x3 CHANGE  The attribute aggregate type has been changed from LIST to SET.
	Types	SET [0:1] OF IfcRelDefinesByType FOR RelatingType	Reference to the relationship IfcRelDefinedByType and thus to those occurrence objects, which are defined by this type.
IfcTypeProcess
7	Identification	OPTIONAL IfcIdentifier	An identifying designation given to a process type.
8	LongDescription	OPTIONAL IfcText	An long description, or text, describing the activity in detail. > NOTE  The inherited _SELF\IfcRoot.Description_ attribute is used as the short description.
9	ProcessType	OPTIONAL IfcLabel	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.
	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 type. > HISTORY New inverse relationship in IFC4.
IfcTaskType
10	PredefinedType	IfcTaskTypeEnum	Identifies the predefined types of a task type from which the type required may be set.
11	WorkMethod	OPTIONAL IfcLabel	The method of work used in carrying out a task.

5.3.3.7.2 Entity inheritance

5.3.3.7.3 Definitions applying to General Usage

5.3.3.7.3.1 Classification Association

5.3.3.7.3.2 Identity

5.3.3.7.3.3 Nesting

5.3.3.7.3.4 Revision Control

5.3.3.7.4 Formal representations

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