IfcCovering

Item	Change	Description
IFC2x3 to IFC4 4.0.0.0
IfcCovering	MOVED	Schema changed from IFCPRODUCTEXTENSION to IFCSHAREDBLDGELEMENTS.
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
IFC4x2 Candidate 4.2.0.0
IfcCovering
PositionedRelativeTo	ADDED
IFC2x3 to IFC4 4.0.0.0
IfcCovering	MOVED	Schema changed from IFCPRODUCTEXTENSION to IFCSHAREDBLDGELEMENTS.
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
IFC4x2 Candidate 4.2.0.0
IfcCovering
PositionedRelativeTo	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	G
9	PredefinedType	IfcCoveringTypeEnum	?	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
	CoversSpaces	IfcRelCoversSpaces @RelatedCoverings	S[0:1]	Reference to the objectified relationship that handles the relationship of the covering to the covered space.	X
	CoversElements	IfcRelCoversBldgElements @RelatedCoverings	S[0:1]	Reference to the objectified relationship that handles the relationship of the covering to the covered element. IFC4 CHANGE Renamed into CoversElements for consistency.	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	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
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). IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.	X
	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). IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.	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. IFC4 CHANGE The inverse attribute datatype has been added.	X
	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). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	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). IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.	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	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.	X
	IsDeclaredBy	IfcRelDefinesByObject @RelatedObjects	S[0:1]	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.	X
	Declares	IfcRelDefinesByObject @RelatingObject	S[0:?]	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.	X
	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. 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.	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. IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	?	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	?	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
	PositionedRelativeTo	IfcRelPositions @RelatedProducts	S[0:1]		X
	ReferencedInStructures	IfcRelReferencedInSpatialStructure @RelatedElements	S[0:?]		X
IfcElement
8	Tag	IfcIdentifier	?	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
	FillsVoids	IfcRelFillsElement @RelatedBuildingElement	S[0:1]	Reference to the IfcRelFillsElement Relationship that puts the element as a filling into the opening created within another element.	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.	X
	IsInterferedByElements	IfcRelInterferesElements @RelatedElement	S[0:?]	Reference to the interference relationship to indicate the element that is interfered. The relationship, if provided, indicates that this element has an interference with one or many other elements. NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship.	X
	InterferesElements	IfcRelInterferesElements @RelatingElement	S[0:?]	Reference to the interference relationship to indicate the element that interferes. The relationship, if provided, indicates that this element has an interference with one or many other elements. NOTE There is no indication of precedence between IsInterferedByElements and InterferesElements. IFC4 CHANGE New inverse relationship.	X
	HasProjections	IfcRelProjectsElement @RelatingElement	S[0:?]	Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.	X
	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
	IsConnectionRealization	IfcRelConnectsWithRealizingElements @RealizingElements	S[0:?]	Reference to the connection relationship with realizing element. The relationship, if provided, assigns this element as the realizing element to the connection, which provides the physical manifestation of the connection relationship.	X
	ProvidesBoundaries	IfcRelSpaceBoundary @RelatedBuildingElement	S[0:?]	Reference to space boundaries by virtue of the objectified relationship IfcRelSpaceBoundary. It defines the concept of an element bounding spaces.	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.	X
	HasCoverings	IfcRelCoversBldgElements @RelatingBuildingElement	S[0:?]	Reference to IfcCovering by virtue of the objectified relationship IfcRelCoversBldgElement. It defines the concept of an element having coverings associated.	X
IfcBuiltElement
IfcCovering
9	PredefinedType	IfcCoveringTypeEnum	?	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
	CoversSpaces	IfcRelCoversSpaces @RelatedCoverings	S[0:1]	Reference to the objectified relationship that handles the relationship of the covering to the covered space.	X
	CoversElements	IfcRelCoversBldgElements @RelatedCoverings	S[0:1]	Reference to the objectified relationship that handles the relationship of the covering to the covered element. IFC4 CHANGE Renamed into CoversElements for consistency.	X

Definitions applying to General Usage

Instance diagram

Concept usage

Object Typing

The Object Typing concept applies to this entity.

Property Sets for Objects

The Property Sets for Objects concept template applies to this entity as shown in Table 123.

PsetName

Properties

Pset_CoveringCommon

Template	PropertyName	Value
Single Value	Reference	IfcIdentifier
Single Value	FireRating	IfcLabel
Single Value	AcousticRating	IfcLabel
Single Value	FlammabilityRating	IfcLabel
Single Value	FragilityRating	IfcLabel
Single Value	SurfaceSpreadOfFlame	IfcLabel
Single Value	Combustible	IfcBoolean
Single Value	IsExternal	IfcBoolean
Single Value	ThermalTransmittance	IfcThermalTransmittanceMeasure
Single Value	Finish	IfcText
Enumerated Value	Status	IfcLabel

Table 123 — IfcCovering Property Sets for Objects

Quantity Sets

The Quantity Sets concept template applies to this entity as shown in Table 124.

QsetName	Quantities
Qto_CoveringBaseQuantities

Table 124 — IfcCovering Quantity Sets

Spatial Containment

The Spatial Containment concept template applies to this entity as shown in Table 125.

RelatingStructure
IfcSpace

Table 125 — IfcCovering Spatial Containment

The IfcCovering has a containment relationship within the hierarchical spatial structure.

The IfcCovering is places within the project spatial hierarchy using the objectified relationship IfcRelContainedInSpatialStructure, referring to it by its inverse attribute SELF\IfcElement.ContainedInStructure. Subtypes of IfcSpatialStructureElement are valid spatial containers, with IfcSpace being the default container.

Material Layer Set Usage

The Material Layer Set Usage concept template applies to this entity as shown in Table 126.

Name	Description
Front	Optional front-facing material of layer-based coverings such as drywall paper.
Fill	The solid material of layer-based coverings such as drywall gypsum.
Back	Optional back-facing material of layer-based coverings such as drywall paper.

Table 126 — IfcCovering Material Layer Set Usage

Coverings for surfaces (CEILING, FLOORING, CLADDING, CEILING, ROOFING) may have materials defined according to layers.

Material Profile Set Usage

The Material Profile Set Usage concept template applies to this entity as shown in Table 127.

Name	Description
Trim	Profile of trim such as crown molding or base molding.

Table 127 — IfcCovering Material Profile Set Usage

Coverings for edges (MOLDING, SKIRTINGBOARD) may have materials defined according to profiles.

Surface Geometry

The Surface Geometry concept applies to this entity.

The following additional constraints apply to the 'GeometricSet' representation of IfcCovering:

for planar base surfaces - bounded surface representation
for cylindrical base surfaces - swept surface representation

	EXAMPLE Figure 213 illustrates a planar surface representation where the area of IfcCovering is given by an IfcPolyLoop for planar base surfaces (here provided by the IfcRelSpaceBoundary). The implicit planar surface of the IfcPolyLoop shall be identical with the planar surface defined by the IfcRelSpaceBoundary.
Figure 213 — Covering surface planar

EXAMPLE Figure 214 illustrates a cylindrical surface representation where the area of the IfcCovering is given by an IfcSurfaceOfLinearExtrusion for cylindrical base surfaces (here given by the IfcRelSpaceBoundary, such as caused by a round wall).

The geometry representation of the IfcCovering is given by the IfcTrimmedCurved (the Curve parameter of the IfcArbitraryOpenProfileDef - in cases of faceted representation also an IfcPolyline). It is extruded within the plane of the base surface using the Depth parameter of the IfcSurfaceOfLinearExtrusion.

Figure 214 — Covering surface cylindrical

Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity.

The following additional constraints apply to the 'SweptSolid' representation of IfcCovering:

for planar base surfaces - swept area representation
for cylindrical base surfaces - swept area representation

	EXAMPLE Figure 215 illustrates a body representation where the volume of IfcCovering is given by an IfcExtrudedAreaSolid for planar base surfaces (here given by the IfcRelSpaceBoundary). The extruded area (IfcArbitraryClosedProfileDef) shall be coplanar to the surface defined by the IfcRelSpaceBoundary.
Figure 215 — Covering body planar

EXAMPLE Figure 216 illustrates a body representation where the volume of the IfcCovering is given by an IfcExtrudedAreaSolid for cylindrical base surfaces (here given by the IfcRelSpaceBoundary - such as caused by a round wall).

The geometry representation of the IfcCovering is given by the IfcCompositeCurve (the OuterCurve parameter of the IfcArbitraryClosedProfileDef - in cases of faceted representation also a closed IfcPolyline). It is extruded along the plane of the base surface using the Depth parameter of the IfcSurfaceOfLinearExtrusion.

Figure 216 — Covering body circular

mvdXML Specification


<?xml version="1.0" encoding="utf-8"?>

<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="71f56697-4f86-45c6-a960-7dbf2c5424a7" name="IfcCovering" applicableRootEntity="IfcCovering">

 <Applicability>

  <Template ref="d24c3034-cab6-4612-9eb8-9f814dd9a3d4" />

  <TemplateRules operator="and">

  </TemplateRules>

 </Applicability>

 <Concepts>

  <Concept uuid="e2c62edc-7fd0-41e4-9e89-5c348b65492f" name="Object Typing">

   <Template ref="35a2e10e-20df-40f4-ab2f-dacf0a6744f4" />

  </Concept>

  <Concept uuid="097c3f91-ba3f-4c90-9503-4873e56e7587" name="Property Sets for Objects">

   <Template ref="f74255a6-0c0e-4f31-84ad-24981db62461" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="PsetName[Value]=&apos;Pset_CoveringCommon&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="397523b1-8cc5-4172-aeac-d1d73f8ab001" name="Quantity Sets">

   <Template ref="6652398e-6579-4460-8cb4-26295acfacc7" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="QsetName[Value]=&apos;Qto_CoveringBaseQuantities&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="c24fd65c-3172-428f-ae20-07886b19ecae" name="Spatial Containment">

   <Template ref="d9a3f822-0014-4bc2-8d94-9d9067759045" />

   <TemplateRules operator="and">

    <TemplateRule Parameters="RelatingStructure[Type]=&apos;IfcSpace&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="1317ca91-462b-4bfe-a951-8b1e0cbd0aa5" name="Material Layer Set Usage">

   <Template ref="6d5fb86f-3f2d-49fb-9528-077855ddcc47" />

   <TemplateRules operator="and">

    <TemplateRule Description="Optional front-facing material of layer-based coverings such as drywall paper." Parameters="Name[Value]=&apos;Front&apos;" />

    <TemplateRule Description="The solid material of layer-based coverings such as drywall gypsum." Parameters="Name[Value]=&apos;Fill&apos;" />

    <TemplateRule Description="Optional back-facing material of layer-based coverings such as drywall paper." Parameters="Name[Value]=&apos;Back&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="9e0bc382-529e-40c9-838f-bf81ca989828" name="Material Profile Set Usage">

   <Template ref="6aa01429-b566-4b36-875a-3162088a9831" />

   <TemplateRules operator="and">

    <TemplateRule Description="Profile of trim such as crown molding or base molding." Parameters="Name[Value]=&apos;Trim&apos;" />

   </TemplateRules>

  </Concept>

  <Concept uuid="e9e34f36-1a74-4ae4-aa59-a4208cfdce63" name="Surface Geometry">

   <Template ref="2e99de70-fb73-478f-9bca-4fedfdeb4ea5" />

  </Concept>

  <Concept uuid="57fa00e6-30ca-4650-8686-9f8fc8fbb90b" name="Body SweptSolid Geometry">

   <Template ref="cb7c18fa-cf83-4db1-be1b-c013ba4ed672" />

  </Concept>

 </Concepts>

</ConceptRoot>

Concept inheritance

#	Concept	Template	Model View
IfcRoot
	Identity	Software Identity	General Usage
	Revision Control	Revision Control	General Usage
IfcObjectDefinition
	Classification Association	Classification Association	General Usage
IfcObject
	Object User Identity	Object User Identity	General Usage
	Object Predefined Type	Object Predefined Type	General Usage
	Property Sets with Override	Property Sets with Override	General Usage
IfcProduct
	Product Placement	Product Placement	General Usage
	Product Geometric Representation	Product Geometric Representation	General Usage
IfcElement
	Product Local Placement	Product Local Placement	General Usage
	CoG Geometry	CoG Geometry	General Usage
	Box Geometry	Box Geometry	General Usage
	FootPrint Geometry	FootPrint Geometry	General Usage
	Body SurfaceOrSolidModel Geometry	Body SurfaceOrSolidModel Geometry	General Usage
	Body SurfaceModel Geometry	Body SurfaceModel Geometry	General Usage
	Body Tessellation Geometry	Body Tessellation Geometry	General Usage
	Body Brep Geometry	Body Brep Geometry	General Usage
	Body AdvancedBrep Geometry	Body AdvancedBrep Geometry	General Usage
	Body CSG Geometry	Body CSG Geometry	General Usage
	Mapped Geometry	Mapped Geometry	General Usage
	Element Voiding	Element Voiding	General Usage
	Element Projecting	Element Projecting	General Usage
	Linear Placement	Product Linear Placement	General Usage
IfcBuiltElement
	Product Assignment	Product Assignment	General Usage
	Surface 3D Geometry	Surface 3D Geometry	General Usage
IfcCovering
	Object Typing	Object Typing	General Usage
	Property Sets for Objects	Property Sets for Objects	General Usage
	Quantity Sets	Quantity Sets	General Usage
	Spatial Containment	Spatial Containment	General Usage
	Material Layer Set Usage	Material Layer Set Usage	General Usage
	Material Profile Set Usage	Material Profile Set Usage	General Usage
	Surface Geometry	Surface Geometry	General Usage
	Body SweptSolid Geometry	Body SweptSolid Geometry	General Usage

	Bekleidung / Belag
	Covering
	Revêtement

IfcCovering

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to General Usage

Formal representations