IFC 4.3.x development

5.1.3.9 IfcProcess

Change log

IFC4

additions attributes Identification
additions attributes LongDescription
modificationsinverses OperatesOn definitionChanged from SET OF [0:?] IfcRelAssignsToProcess FOR RelatingProcess to SET OF [0:?] IfcRelSequence FOR RelatingProcess
modificationsinverses OperatesOn name Changed from OperatesOn to IsPredecessorTo

5.1.3.9.1 Semantic definitions at the entity

IfcProcess is defined as one individual activity or event, that is ordered in time, that has sequence relationships with other processes, which transforms input in output, and may connect to other other processes through input output relationships. An IfcProcess can be an activity (or task), or an event. It takes usually place in building construction with the intent of designing, costing, acquiring, constructing, or maintaining products or other and similar tasks or procedures. Figure 1 illustrates process relationships.

NOTE  Definition according to ISO9000:
A process is a set of activities that are interrelated or that interact with one another. Processes use resources to transform inputs into outputs. Processes are interconnected because the output from one process becomes the input for another process. In effect, processes are "glued" together by means of such input output relationships.

"icon diagram"

Process information relates to other objects by establishing the following relationships:

  • Nesting of processes : IfcRelNests - A process can contain sub processes and thereby be nested.
  • Sequencing of processes : IfcRelSequence - Processes can be placed in sequence (including overlapping for parallel tasks), and have predecessors and successors.
  • Assigning process to schedules : IfcRelAssignsToControl - Activities such as tasks, and predominately summary tasks, are assigned to a work schedule.
  • Having a product assigned to the process as input : IfcRelAssignsToProcess - Products can be assigned as input to a process, such as for construction process planning.
  • Having a product assigned to the process as output : IfcRelAssignsToProduct - Products can be assigned as output to a process, such as for construction process planning.
  • Having a control assigned to the process as process control : IfcRelAssignsToProcess - Items that act as a control onto the process can be assigned to a process, such as for cost management (a cost item assigned to a work task).
  • Having a resource assigned to the process as consumed by the process : IfcRelAssignsToProcess - Items that act as a mechanism to a process, such as labor, material and equipment in cost calculations.

HISTORY  New entity in IFC1.0.

IFC2x CHANGE  The attribute Productivity has been removed.

IFC4 CHANGE  The attribute Identification has been promoted from subtypes IfcTask and others.

5.1.3.9.1 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.
HasAssociationsSET [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.
IfcObject
5 ObjectType OPTIONAL 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.
IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects 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.
Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject 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.
IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects 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.
IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjectsSet 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.
IfcProcess
6 Identification OPTIONAL IfcIdentifier An identifying designation given to a process or activity.

It is the identifier at the occurrence level.



> IFC4 CHANGE Attribute promoted from subtypes.
7 LongDescriptionOPTIONAL IfcText An extended description or narrative that may be provided.

> IFC4 CHANGE  New attribute.
IsPredecessorToSET [0:?] OF IfcRelSequence FOR RelatingProcess 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.
IsSuccessorFromSET [0:?] OF IfcRelSequence FOR RelatedProcess 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.
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.

5.1.3.9.2 Entity inheritance

dot_inheritance IfcEvent IfcEvent IfcProcess IfcProcess IfcEvent->IfcProcess IfcObject IfcObject IfcProcess->IfcObject IfcProcedure IfcProcedure IfcProcedure->IfcProcess IfcTask IfcTask IfcTask->IfcProcess IfcObject_children 5 more... IfcObject_children->IfcObject IfcObjectDefinition IfcObjectDefinition IfcObject->IfcObjectDefinition IfcContext IfcContext IfcContext->IfcObjectDefinition IfcRoot IfcRoot IfcObjectDefinition->IfcRoot IfcTypeObject IfcTypeObject IfcTypeObject->IfcObjectDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertyDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

5.1.3.9.3 Definitions applying to General Usage

5.1.3.9.3.1 Classification Association

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

5.1.3.9.3.2 Identity

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

5.1.3.9.3.3 Object Predefined Type

5.1.3.9.3.4 Object Typing

Any object occurrence can be typed by being assigned to a common object type utilizing this concept. A particular rule, restricting the applicable subtypes of IfcTypeObject that can be assigned, is introduced by overriding this concept at the level of subtypes of IfcObject.

5.1.3.9.3.5 Object User Identity

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as ifcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

5.1.3.9.3.6 Property Sets for Objects

PsetName
'Pset_Risk'

5.1.3.9.3.7 Property Sets with Override

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case, that the same property (within the same property set, is defined both, in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

5.1.3.9.3.8 Revision Control

Ownership, history, and merge state is captured using IfcOwnerHistory.

5.1.3.9.4 Formal representations

ENTITY IfcProcess
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcEvent
	,IfcProcedure
	,IfcTask))
 SUBTYPE OF (IfcObject);
	Identification : OPTIONAL IfcIdentifier;
	LongDescription : OPTIONAL IfcText;
 INVERSE
	IsPredecessorTo : SET [0:?] OF IfcRelSequence FOR RelatingProcess;
	IsSuccessorFrom : SET [0:?] OF IfcRelSequence FOR RelatedProcess;
	OperatesOn : SET [0:?] OF IfcRelAssignsToProcess FOR RelatingProcess;
END_ENTITY;