IfcCovering

Item	Change	Description
IFC2x3 to IFC4
IfcCovering	MOVED	Schema changed from IFCPRODUCTEXTENSION to IFCSHAREDBLDGELEMENTS.
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
IFC4x1 to IFC4x2
IfcCovering
PositionedFrom	ADDED

Semantic definitions at the entity

Entity definition

A covering is an element which covers some part of another element and is fully dependent on that other element. The IfcCovering defines the occurrence of a covering type, that (if given) is expressed by the IfcCoveringType.

NOTE Definition according to ISO ISO 6707-1: final coverings and treatments of surfaces and their intersections.

Coverings are elements with relationships to the covered element and the space on the other side, they may contain openings, assigned by IfcRelVoidsElement, material information, assigned by IfcRelAssociatesMaterial, and others.

EXAMPLE Coverings include wall claddings, floorings, suspended ceilings, moldings and skirting boards.

NOTE A more basic information about claddings, floorings, and ceilings of a space can be attached to IfcSpace's using the Pset_SpaceCommon properties. Then only a name can be provided and the covering quantities would be interpreted from the space quantities.

Coverings can be assigned to

a space represented by IfcSpace
- using the inverse relationship CoversSpaces pointing to IfcRelCoversSpaces. The space is then accessible via IfcRelCoversSpaces.RelatedSpace. It defines to which space a covering is facing towards.
a space boundary represented by IfcRelSpaceBoundary
- using the inverse relationship ProvidesBoundaries pointing to IfcRelSpaceBoundary. The space is then accessible via IfcRelSpaceBoundary.RelatingSpace.
a building element represented by IfcBuildingElement
- using the inverse relationship Covers pointing to IfcRelCoversBldgElements. The building element is then accessible via IfcRelCoversBldgElements.RelatingBuildingElement.

NOTE The mere containment relationship between an IfcCovering and an IfcSpace is created by using IfcRelContainedInSpatialStructure

The following guideline shall apply:

(default) if the space has coverings that may not have their own shape representation and no defined relationships to the building elements they cover, then the IfcCovering shall be assigned to IfcSpace using the IfcRelCoversSpaces relationship,
if the space has coverings that have an own shape representation and the space has defined space boundaries, then the covering, which relates to that space, shall be contained in the space using IfcRelContainedInSpatialStructure. It may be assigned to the space boundaries using the IfcRelSpaceBoundary.
if the covering does not relate to a space, then the covering should be assigned to the building element or a distribution element using the IfcRelCoversBldgElements relationship.

HISTORY New entity in IFC1.0.

IFC2x CHANGE The attribute PredefinedType is now optional and should only be inserted when no type information, given by IfcCoveringType, is assigned to the IfcCovering occurrence by IfcRelDefinesByType.

Attribute definitions

#	Attribute	Type	Cardinality	Description	B
9	PredefinedType	IfcCoveringTypeEnum	[0:1]	Predefined types to define the particular type of the covering. There may be property set definitions available for each predefined type. NOTE The PredefinedType shall only be used, if no IfcCoveringType is assigned, providing its own IfcCoveringType.PredefinedType.	X

Formal Propositions

Rule	Description
CorrectPredefinedType	Either the PredefinedType attribute is unset (e.g. because an IfcCoveringType is associated), or the inherited attribute ObjectType shall be given, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssigned	Either there is no covering type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcCoveringType.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	B
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	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.	X
3	Name	IfcLabel	[0:1]	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	[0:1]	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).
	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).	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.
	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).	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).	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
IfcObject
5	ObjectType	-		This attribute is out of scope for this model view definition and shall not be set.
	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.	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.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	[0:1]	Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system.	X
7	Representation	IfcProductRepresentation	[0:1]	Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement.	X
	ReferencedBy	IfcRelAssignsToProduct @RelatingProduct	S[0:?]	Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product.	X
IfcElement
8	Tag	IfcIdentifier	[0:1]	The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level.	X
	ConnectedTo	IfcRelConnectsElements @RelatingElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.
	HasOpenings	IfcRelVoidsElement @RelatingBuildingElement	S[0:?]	Reference to the IfcRelVoidsElement relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship IfcRelVoidsElement is generated.	X
	ConnectedFrom	IfcRelConnectsElements @RelatedElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.	X
	ContainedInStructure	IfcRelContainedInSpatialStructure @RelatedElements	S[0:1]	Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure.
	PositionedFrom	IfcRelPositions @RelatingElement	S[0:1]	Indicates a constrained placement, where the ObjectPosition must match positioning defined according to the referenced positioning element.	X
IfcBuildingElement
IfcCovering
9	PredefinedType	IfcCoveringTypeEnum	[0:1]	Predefined types to define the particular type of the covering. There may be property set definitions available for each predefined type. NOTE The PredefinedType shall only be used, if no IfcCoveringType is assigned, providing its own IfcCoveringType.PredefinedType.	X

Definitions applying to Bridge View

Instance diagram

Concept usage

Object Typing

The Object Typing concept applies to this entity.

Exchange
Import		O
Export		O

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Bridge View
	User Identity	Bridge View
	Object Ownership	Bridge View
IfcObject
	Property Sets for Objects	Bridge View
IfcElement
	Element Occurrence Attributes	Bridge View
	Product Local Placement	Bridge View
	Product Assignment	Bridge View
IfcCovering
	Object Typing	Bridge View

Formal representations

XSD Specification

 <xs:element name="IfcCovering" type="ifc:IfcCovering" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>

 <xs:complexType name="IfcCovering">

  <xs:complexContent>

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

    <xs:attribute name="PredefinedType" type="ifc:IfcCoveringTypeEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcCovering

 SUBTYPE OF (IfcBuildingElement);

  PredefinedType : OPTIONAL IfcCoveringTypeEnum;

 INVERSE

 WHERE

  CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR 
 (PredefinedType <> IfcCoveringTypeEnum.USERDEFINED) OR 
 ((PredefinedType = IfcCoveringTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
  CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR
  ('IFCSHAREDBLDGELEMENTS.IFCCOVERINGTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

 EXPRESS-G diagram

Link to this page

	Bekleidung / Belag
	Covering
	Revêtement