IfcRelInterferesElements

Item	SPF	XML	Change	Description
IFC2x3 to IFC4
IfcRelInterferesElements			ADDED

Semantic definitions at the entity

Entity definition

The IfcRelInterferesElements objectified relationship indicates that two elements interfere. Interference is a spatial overlap between the two elements. It is a 1 to 1 relationship. The concept of two elements interfering physically or logically is described independently from the elements. The interference may be related to the shape representation of the entities by providing an interference geometry.

When the interference geometry is available it can be passed by the optional attribute InterferenceGeometry pointing to IfcConnectionGeometry. The connection geometry is provided as a point, curve, surface, or volume within the local placement coordinate systems of the connecting elements. The IfcConnectionVolumeGeometry is the default type to be used for interference in 3D space, as indicated in e.g. clash detections.
If the interference geometry is omitted then the interference is provided as a logical relationship. Under this circumstance, the connection point, curve, surface, or solid has to be recalculated by the receiving application.

The RelatingElement and RelatedElement define the two elements in the relationship, that may have different roles. This is controlled by the attribute ImpliedOrder.

ImpliedOrder=TRUE The RelatingElement constitutes the primary element of the interference relationship. If the interference is to be resolved by subtracting the overlapping part, it should be subtracted from the RelatingElement. The net result would be the RelatingElement subtracted by the InterferenceGeometry. This would be the case in interference relationships where the RelatedElement creates a void in the RelatingElement dynamically.
ImpliedOrder=FALSE The RelatingElement and RelatedElement have no priority among each other. If the interference is to be resolved then no information about whether the InterferenceGeometry should be subtracted from the RelatingElement or thed RelatedElement can be traced. This would be the case for clash detection results.
ImpliedOrder=UNKNOWN No information about the priorities is provided.

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
5	RelatingElement	IfcElement		Reference to a subtype of IfcElement that is the RelatingElement in the interference relationship. Depending on the value of ImpliedOrder the RelatingElement may carry the notion to be the element from which the interference geometry should be subtracted.	X
6	RelatedElement	IfcElement		Reference to a subtype of IfcElement that is the RelatedElement in the interference relationship. Depending on the value of ImpliedOrder the RelatedElement may carry the notion to be the element from which the interference geometry should not be subtracted.	X
7	InterferenceGeometry	IfcConnectionGeometry	?	The geometric shape representation of the interference geometry that is provided in the object coordinate system of the RelatingElement (mandatory) and in the object coordinate system of the RelatedElement (optionally).	X
8	InterferenceType	IfcIdentifier	?	Optional identifier that describes the nature of the interference. Examples could include 'Clash', 'ProvisionForVoid', etc.	X
9	ImpliedOrder	LOGICAL		Logical value indicating whether the interference geometry should be subtracted from the RelatingElement (if TRUE), or whether it should be either subtracted from the RelatingElement or the RelatedElement (if FALSE), or whether no indication can be provided (if UNKNOWN).	X

Formal Propositions

Rule	Description
NotSelfReference	The instance of the RelatingElement shall not be the same instance as the RelatedElement.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRoot
1	GlobalId	IfcGloballyUniqueId		Assignment of a globally unique identifier within the entire software world.	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
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
4	Description	IfcText	?	Optional description, provided for exchanging informative comments.	X
IfcRelationship
IfcRelConnects
IfcRelInterferesElements
5	RelatingElement	IfcElement		Reference to a subtype of IfcElement that is the RelatingElement in the interference relationship. Depending on the value of ImpliedOrder the RelatingElement may carry the notion to be the element from which the interference geometry should be subtracted.	X
6	RelatedElement	IfcElement		Reference to a subtype of IfcElement that is the RelatedElement in the interference relationship. Depending on the value of ImpliedOrder the RelatedElement may carry the notion to be the element from which the interference geometry should not be subtracted.	X
7	InterferenceGeometry	IfcConnectionGeometry	?	The geometric shape representation of the interference geometry that is provided in the object coordinate system of the RelatingElement (mandatory) and in the object coordinate system of the RelatedElement (optionally).	X
8	InterferenceType	IfcIdentifier	?	Optional identifier that describes the nature of the interference. Examples could include 'Clash', 'ProvisionForVoid', etc.	X
9	ImpliedOrder	LOGICAL		Logical value indicating whether the interference geometry should be subtracted from the RelatingElement (if TRUE), or whether it should be either subtracted from the RelatingElement or the RelatedElement (if FALSE), or whether no indication can be provided (if UNKNOWN).	X

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General Usage

Formal representations

XML Specification

 <xs:element name="IfcRelInterferesElements" type="ifc:IfcRelInterferesElements" substitutionGroup="ifc:IfcRelConnects" nillable="true"/>

 <xs:complexType name="IfcRelInterferesElements">

  <xs:complexContent>

   <xs:extension base="ifc:IfcRelConnects">

    <xs:sequence>

     <xs:element name="RelatingElement" type="ifc:IfcElement" nillable="true"/>

     <xs:element name="RelatedElement" type="ifc:IfcElement" nillable="true"/>

     <xs:element name="InterferenceGeometry" type="ifc:IfcConnectionGeometry" nillable="true" minOccurs="0"/>

    </xs:sequence>

    <xs:attribute name="InterferenceType" type="ifc:IfcIdentifier" use="optional"/>

    <xs:attribute name="ImpliedOrder" type="ifc:logical" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcRelInterferesElements

 SUBTYPE OF (IfcRelConnects);

  RelatingElement : IfcElement;

  RelatedElement : IfcElement;

  InterferenceGeometry : OPTIONAL IfcConnectionGeometry;

  InterferenceType : OPTIONAL IfcIdentifier;

  ImpliedOrder : LOGICAL;

 WHERE

  NotSelfReference : RelatingElement :<>: RelatedElement;
END_ENTITY;

 EXPRESS-G diagram

	Kollision zwischen Elementen - Relation
	Rel Interferes Elements

IfcRelInterferesElements

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations