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IfcRelSequence

Definition from IAI: This objectified relationship handles the concatenation of processes over time. The sequence is defined as relationship between two processes. The related object is the successor of the relating object, being the predecessor. A time lag is assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence.

IfcRelSequence is defined as an one-to-one relationship, therefore it assigns one predecessor to one successor. However, each IfcProcess can have multiple predecessors and successors, as the sequence relationship is truly an N-to-M relationship.

HISTORY: New entity in IFC Release 1.0.

EXPRESS specification:

ENTITY IfcRelSequence
SUBTYPE OF ( IfcRelConnects);
RelatingProcess  :  IfcProcess;
RelatedProcess  :  IfcProcess;
TimeLag  :  IfcTimeMeasure;
SequenceType  :  IfcSequenceEnum;
WHERE
WR1  :  RelatingProcess :<>: RelatedProcess;
END_ENTITY;

Attribute definitions:

RelatingProcess  :  Reference to the Process, that is the predecessor.
RelatedProcess  :  Reference to the Process, that is the successor.
TimeLag  :  Time Duration of the sequence, it is the time lag between the predecessor and the successor as specified by the SequenceType.
SequenceType  :  The way in which the time lag applies to the sequence.

Formal Propositions:

WR1  :  The RelatingProcess shall not point to the same instance as the RelatedProcess.

Inheritance graph

ENTITY IfcRelSequence;
ENTITY IfcRoot;
GlobalId  :  IfcGloballyUniqueId;
OwnerHistory  :  IfcOwnerHistory;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ENTITY IfcRelationship;
ENTITY IfcRelConnects;
ENTITY IfcRelSequence;
RelatingProcess  :  IfcProcess;
RelatedProcess  :  IfcProcess;
TimeLag  :  IfcTimeMeasure;
SequenceType  :  IfcSequenceEnum;
END_ENTITY;