IfcTask

BACnet MVD

#### IfcTask

Natural language names

| Aufgabe
| Task
| Tâche

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcTask |  |  |  |
OwnerHistory |  |  | MODIFIED | Instantiation changed to OPTIONAL.
Identification |  | X | MODIFIED | Name changed from TaskId to Identification. Instantiation changed to OPTIONAL.
LongDescription |  |  | MODIFIED | Name changed from Status to LongDescription. Type changed from IfcLabel to IfcText.
Status |  | X | MODIFIED | Name changed from WorkMethod to Status.
WorkMethod | X | X | MODIFIED | Name changed from IsMilestone to WorkMethod. Type changed from BOOLEAN to IfcLabel. Instantiation changed to OPTIONAL.
IsMilestone | X | X | MODIFIED | Name changed from Priority to IsMilestone. Type changed from INTEGER to BOOLEAN. Instantiation changed from OPTIONAL.
Priority |  |  | ADDED |
TaskTime |  |  | ADDED |
PredefinedType |  |  | ADDED |
IFC4 Addendum 1
IfcTask |  |  |  |
IsMilestone |  |  | MODIFIED | Type changed from BOOLEAN to IfcBoolean.
Priority |  |  | MODIFIED | Type changed from INTEGER to IfcInteger.

##### Semantic definitions at the entity

Entity definition

An IfcTask is an identifiable unit of work to be carried out in a construction project.

A task is typically used to describe an activity for the construction or installation of products, but is not limited to these types. For example it might be used to describe design processes, move operations and other design, construction and operation related activities as well.

Quantities of resources consumed by the task are dealt with by defining the IfcElementQuantity for the resource and not at the instance of IfcTask.

> HISTORY New entity in IFC1.0. Renamed from IfcWorkTask in IFC2x.

> IFC4 CHANGE Attributes TaskTime and PredefinedType added. IfcMove and IfcOrderRequest has been removed in IFC4 and are now represented by IfcTask. IfcRelAssignsTasks relationship has been removed as well.

Attribute use definition

Each occurrence of IfcTask is given a name that is indicative of its content (IfcRoot.Name). A textual description of the task may be provided and this may be further elaborated by a narrative long description (IfcProcess.LongDescription). A work method may be declared for the method of work used in carrying out a task. A task is identified as being either a milestone task or not. A milestone task is defined by the marker IsMilestone. and has no duration. A status and priority for each task may also be set.

Time and duration use definition

Compared to previous IFC releases, basic task time information (scheduled start time, scheduled finish time, duration) is now directly attached to IfcTask through the TaskTime attribute. Regular tasks are defined through IfcTaskTime. Recurring tasks are defined through IfcTaskTimeRecurring. In case a regular task is derived from a recurring task both tasks should be linked together through a IfcRelNests relationship, where IfcRelNests.IsNestedBy points to the recurring task and IfcRelNests.Nests points to all regular tasks that have been derived from the recurring task.

Representation of other activities

The use definitions for IfcTask have been generalised to represent other activities as well, including activities that had been defined by own entities in previous IFC releases. This includes

- Order actions
- Move operations

IfcTask represents an order that might be carried out by a Helpdesk acting the role of interface for the organization between the facility user and the functional requirement of fulfilling their needs. The actual task represented by the IfcTask entity is turning a request into an order and initiating the action that will enable the order to be completed. The IfcProjectOrder or one of its subtypes including maintenance work order, is related to the IfcTask using IfcRelAssignsToControl.

IfcTask can also be used to describe an activity that moves people, groups within an organization or complete organizations together with their associated furniture and equipment from one place to another. It thus replaces the previous IFC entity IfcMove. The functionality is represented in IfcTask as follows:

- Move from: The place from which actors and their associated equipment are moving.
  Use IfcRelAssignsToProcess where RelatingProcess points to the task and RelatedObjects holds the location(s) from which to move.
- Move to: The place to which actors and their associated equipment are moving.
  Use IfcRelAssignsToProduct where RelatedObjects points to the task(s) and RelatingProduct points to the location to which to move.
- Punch list: A list of points concerning a move that require attention.
  Use LongDescription or else identify sub-tasks to track punch list items individually via IfcRelNests.

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---

8

Status

IfcLabel

?

Current status of the task.

> NOTE Particular values for status are not specified, these should be determined and agreed by local usage. Examples of possible status values include 'Not Yet Started', 'Started', 'Completed'.

X

9

WorkMethod

IfcLabel

?

The method of work used in carrying out a task.

> NOTE This attribute should not be used if the work method is specified for the IfcTaskType

X

10

IsMilestone

IfcBoolean

Identifies whether a task is a milestone task (=TRUE) or not (= FALSE).

> NOTE In small project planning applications, a milestone task may be understood to be a task having no duration. As such, it represents a singular point in time.

X

11 | Priority | IfcInteger | ? | A value that indicates the relative priority of the task (in comparison to the priorities of other tasks). |  | X

12

TaskTime

IfcTaskTime

?

Time related information for the task.

> IFC4 CHANGE Attribute added

X

13

PredefinedType

IfcTaskTypeEnum

?

Identifies the predefined types of a task from which the type required may be set.

> IFC4 CHANGE Attribute added

X

Formal Propositions

Rule | Description
--- | ---
HasName | The Name attribute should be inserted to describe the task name.
CorrectPredefinedType | The attribute ObjectType must be asserted when the value of PredefinedType is set to USERDEFINED.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRoot
1 | GlobalId | IfcGloballyUniqueId |  | Assignment of a globally unique identifier within the entire software world. | X | X

2

OwnerHistory

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.

X

X

3 | Name | 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. | X | X
4 | Description | IfcText | ? | 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).

> IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.

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).

> IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.

X

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.

> IFC4 CHANGE The inverse attribute datatype has been added.

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).

> IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.

X

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).

> IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.

X

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 | X
IfcObject

5

ObjectType

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.

X

IsDeclaredBy

IfcRelDefinesByObject
@RelatedObjects

S[0:1]

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.

X

X

Declares

IfcRelDefinesByObject
@RelatingObject

S[0:?]

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.

X

IsTypedBy

IfcRelDefinesByType
@RelatedObjects

S[0:1]

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.

X

IsDefinedBy

IfcRelDefinesByProperties
@RelatedObjects

S[0:?]

Set 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.

X

IfcProcess

6

Identification

IfcIdentifier

?

An identifying designation given to a process or activity. It is the identifier at the occurrence level.

> IFC4 CHANGE Attribute promoted from subtypes.

X

7

LongDescription

IfcText

?

An extended description or narrative that may be provided.

> IFC4 CHANGE New attribute.

X

| IsPredecessorTo | IfcRelSequence @RelatingProcess | S[0:?] | 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. |  | X
| IsSuccessorFrom | IfcRelSequence @RelatedProcess | S[0:?] | 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. |  | 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. |  | X
IfcTask

8

Status

IfcLabel

?

Current status of the task.

> NOTE Particular values for status are not specified, these should be determined and agreed by local usage. Examples of possible status values include 'Not Yet Started', 'Started', 'Completed'.

X

9

WorkMethod

IfcLabel

?

The method of work used in carrying out a task.

> NOTE This attribute should not be used if the work method is specified for the IfcTaskType

X

10

IsMilestone

IfcBoolean

Identifies whether a task is a milestone task (=TRUE) or not (= FALSE).

> NOTE In small project planning applications, a milestone task may be understood to be a task having no duration. As such, it represents a singular point in time.

X

11 | Priority | IfcInteger | ? | A value that indicates the relative priority of the task (in comparison to the priorities of other tasks). |  | X

12

TaskTime

IfcTaskTime

?

Time related information for the task.

> IFC4 CHANGE Attribute added

X

13

PredefinedType

IfcTaskTypeEnum

?

Identifies the predefined types of a task from which the type required may be set.

> IFC4 CHANGE Attribute added

X

##### Definitions applying to Design Transfer View

Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View

##### Definitions applying to BACnet View

Instance diagram

#####

Concept usage

BACnet-Task Assign to Controllor

The BACnet-Task Assign to Controllor concept applies to this entity.

BACnet ObjectDefinition Composition

The BACnet ObjectDefinition Composition concept applies to this entity.

Object User Identity

The Object User Identity concept applies to this entity.

Software Identity

The Software Identity concept applies to this entity.

Object Predefined Type

The Object Predefined Type concept applies to this entity.

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 5.

PsetName | Properties
--- | ---

Pset_BACnetProgramObject

Template | PropertyName | Value | Reference
--- | --- | --- | ---
Enumerated Value | Program State | IfcLabel | PEnum_BACnetProgramState
Enumerated Value | Status Flags | IfcLabel | PEnum_BACnetStatusFlag
Single Value | Out of Service | IfcBoolean |
Single Value | Out of Service | IfcBoolean |
Enumerated Value | Program State | IfcLabel | PEnum_BACnetProgramState
Enumerated Value | Status Flags | IfcLabel | PEnum_BACnetStatusFlag

Table 5 — IfcTask Property Sets for Objects

mvdXML Specification
`<?xml version="1.0"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="ffe8eb1d-38b0-435c-8ca2-3d7248daa1bc" name="IfcTask" status="sample" applicableRootEntity="IfcTask">
<Concepts>
<Concept uuid="680b27fb-0daf-427e-8935-52de46dc7803" name="BACnet-Task Assign to Controllor" status="sample" override="false">
<Template ref="e61bfc30-a79e-40d4-a803-abff77645614" />
<Requirements>
<Requirement applicability="import" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
</Concept>
<Concept uuid="733b5a55-4611-4bf6-9833-4da8ff3748b1" name="BACnet ObjectDefinition Composition" status="sample" override="false">
<Template ref="c8ce5b1b-84be-4e74-971f-0f7a5e0a654b" />
<Requirements>
<Requirement applicability="import" requirement="recommended" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="recommended" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
</Concept>
<Concept uuid="95203dad-8066-4a59-ab6b-a0ca9dd66d8c" name="Object User Identity" status="sample" override="false">
<Template ref="c19ec186-9cfd-47fc-a4d4-9fb35008d04a" />
<Requirements>
<Requirement applicability="import" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
</Concept>
<Concept uuid="8e5e983b-45e9-486e-a9cb-ac6417474a05" name="Software Identity" status="sample" override="false">
<Template ref="f7cb0a08-fee7-4cc0-85fe-43f6a6a0bce1" />
<Requirements>
<Requirement applicability="import" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
</Concept>
<Concept uuid="e9002ba4-11a6-42ab-b6bb-a3e04507ce47" name="Object Predefined Type" status="sample" override="false">
<Template ref="25248261-98df-4d0a-9364-5653575ca421" />
<Requirements>
<Requirement applicability="import" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
</Concept>
<Concept uuid="4c33fcfa-114e-4747-8ac6-8d958e0b2837" name="Property Sets for Objects" status="sample" override="false">
<Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />
<Requirements>
<Requirement applicability="import" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
<Requirement applicability="export" requirement="mandatory" exchangeRequirement="b8a611d3-6f94-4bdf-b974-b74089a6e6c7" />
</Requirements>
<TemplateRules operator="and">
<TemplateRule Parameters="PsetName[Value]='Pset_BACnetProgramObject'" />
</TemplateRules>
</Concept>
</Concepts>
</ConceptRoot>
`
Concept inheritance

# | Concept | Template | Model View
--- | --- | --- | ---
IfcRoot
| Revision Control | Revision Control | Design Transfer View
IfcTask
| BACnet-Task Assign to Controllor | BACnet-Task Assign to Controllor | BACnet View
| BACnet ObjectDefinition Composition | BACnet ObjectDefinition Composition | BACnet View
| Object User Identity | Object User Identity | BACnet View
| Software Identity | Software Identity | BACnet View
| Object Predefined Type | Object Predefined Type | BACnet View
| Property Sets for Objects | Property Sets for Objects | BACnet View

##### Formal representations

XML Specification
`<xs:element name="IfcTask" type="ifc:IfcTask" substitutionGroup="ifc:IfcProcess" nillable="true"/>
<xs:complexType name="IfcTask">
<xs:complexContent>
<xs:extension base="ifc:IfcProcess">
<xs:sequence>
<xs:element name="TaskTime" type="ifc:IfcTaskTime" nillable="true" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="Status" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="WorkMethod" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="IsMilestone" type="ifc:IfcBoolean" use="optional"/>
<xs:attribute name="Priority" type="ifc:IfcInteger" use="optional"/>
<xs:attribute name="PredefinedType" type="ifc:IfcTaskTypeEnum" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcTask
SUBTYPE OF (IfcProcess);
Status : OPTIONAL IfcLabel;
WorkMethod : OPTIONAL IfcLabel;
IsMilestone : IfcBoolean;
Priority : OPTIONAL IfcInteger;
TaskTime : OPTIONAL IfcTaskTime;
PredefinedType : OPTIONAL IfcTaskTypeEnum;
WHERE
HasName : EXISTS(SELF\IfcRoot.Name);
CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcTaskTypeEnum.USERDEFINED) OR ((PredefinedType = IfcTaskTypeEnum.USERDEFINED) AND EXISTS(SELF\IfcObject.ObjectType));
END_ENTITY;

EXPRESS-G diagram

`

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