IfcRelInterferesElements

Item	SPF	XML	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcRelInterferesElements			ADDED
IFC4x2 to IFC4x3_RC1
IfcRelInterferesElements
RelatingElement			MODIFIED	Type changed from IfcElement to IfcInterferenceSelect.
RelatedElement			MODIFIED	Type changed from IfcElement to IfcInterferenceSelect.
ImpliedOrder			MODIFIED	Type changed from LOGICAL to IfcLogical.
IFC4x3_RC3 to IFC4x3_RC4
IfcRelInterferesElements
InterferenceSpace	X	X	MODIFIED	Name changed from InterferenceType to InterferenceSpace. Type changed from IfcIdentifier to IfcSpatialZone. Xsdformat changed from Default to Element.
InterferenceType	X	X	MODIFIED	Name changed from ImpliedOrder to InterferenceType. Type changed from IfcLogical to IfcIdentifier. Instantiation changed to OPTIONAL.
ImpliedOrder			ADDED

Semantic definitions at the entity

Entity definition

The IfcRelInterferesElements objectified relationship indicates that two elements interfere. It is a 1 to 1 relationship, and the concept of two elements interfering physically or logically is described independently of the elements.

The interference may be related to the shape representation of the entities by providing an interference geometry or zone:

when the interference is between two physical products, the InterferenceGeometry attribute is used to define the physical interference shape, it can be part of the shape of one of the elements used in the relationship or define the interface between the two shapes using a IfcConnectionGeometry.
when the interference is between two spatial objects, the InterferenceSpace attribute is used to define the interference space between the two footprints associated to the spatial objects, expressed by a specific IfcSpatialZone of predefined type IfcSpatialZoneTypeEnum INTERFERENCE.

If the interference geometry and Zone are 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. Both InterferenceGeometry and InterferenceSpace should not be set together.

The RelatingElement and RelatedElement define the two elements in the relationship, that may have different roles. The relation orientation may be required by certain InterferenceType values or InterferenceGeometry calculation, this is done by setting the attribute ImpliedOrder accordingly:

ImpliedOrder=TRUE The RelatingElement constitutes the primary element of the interference relationship that is oriented from RelatingElement (source) to RelatedElement (target). 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 the RelatedElement can be traced. This would be the case for clash detection results.
ImpliedOrder=UNKNOWN No information about the priorities is provided.

The InterferenceType property optionally specifies the type of interference between the two elements, two set of default types are provided:

Oriented interferences types imply usage of ImpliedOrder set to TRUE and specific choice of RelatingElement and RelatedElement to be meaningful:
- Crosses: the RelatingElement is crossing the RelatedElement (e.g. Railway crossing a road)
- PassesThrough: the RelatingElement is passing through the RelatedElement (e.g. a Road passing inside a tunnel)
- PassesOver: the RelatingElement is passing over the RelatedElement (e.g a bridge passing over a water canal)
- PassesUnder: the RelatingElement is passing under the RelatedElement (e.g a Tunnel passing under a road)
Non oriented interferences types do not imply specific values of ImpliedOrder (but can still be set to detail shape interference calculation)
- Clash: The RelatingElement and RelatedElement have a spatial or shape-based clash
- Along: The RelatingElement and RelatedElement have a common frontier/surface

HISTORY New entity in IFC4.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
5	RelatingElement	IfcInterferenceSelect			X
6	RelatedElement	IfcInterferenceSelect			X
7	InterferenceGeometry	IfcConnectionGeometry	?		X
8	InterferenceType	IfcIdentifier	?	Optional identifier that describes the nature of the interference.	X
9	ImpliedOrder	IfcLogical		Logical value indicating if the RelatingElement is considered a source and the RelatedElement a target (giving a formal orientation to the relation). It shall be provided in regards to InterferenceGeometry usage and InterferenceType declaration.	X
10	InterferenceSpace	IfcSpatialZone	?	Optional attribute that expresses the interfering space for IfcSpatialElement occurrences.	X

Formal Propositions

Rule	Description
NoSelfReference	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	IfcInterferenceSelect			X
6	RelatedElement	IfcInterferenceSelect			X
7	InterferenceGeometry	IfcConnectionGeometry	?		X
8	InterferenceType	IfcIdentifier	?	Optional identifier that describes the nature of the interference.	X
9	ImpliedOrder	IfcLogical		Logical value indicating if the RelatingElement is considered a source and the RelatedElement a target (giving a formal orientation to the relation). It shall be provided in regards to InterferenceGeometry usage and InterferenceType declaration.	X
10	InterferenceSpace	IfcSpatialZone	?	Optional attribute that expresses the interfering space for IfcSpatialElement occurrences.	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">

      <xs:complexType>

       <xs:group ref="ifc:IfcInterferenceSelect"/>

      </xs:complexType>

     </xs:element>

     <xs:element name="RelatedElement">

      <xs:complexType>

       <xs:group ref="ifc:IfcInterferenceSelect"/>

      </xs:complexType>

     </xs:element>

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

     <xs:element name="InterferenceSpace" type="ifc:IfcSpatialZone" nillable="true" minOccurs="0"/>

    </xs:sequence>

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

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

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcRelInterferesElements

 SUBTYPE OF (IfcRelConnects);

  RelatingElement : IfcInterferenceSelect;

  RelatedElement : IfcInterferenceSelect;

  InterferenceGeometry : OPTIONAL IfcConnectionGeometry;

  InterferenceType : OPTIONAL IfcIdentifier;

  ImpliedOrder : IfcLogical;

  InterferenceSpace : OPTIONAL IfcSpatialZone;

 WHERE

  NoSelfReference : 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