IfcPlate

Semantic definitions at the entity

Entity definition

An IfcPlate is a planar and often flat part with constant thickness. A plate can be a structural part carrying loads between or beyond points of support, however it is not required to be load bearing. The location of the plate (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcWall and IfcSlab (as floor slab)).

NOTE Plates are normally made of steel, other metallic material, or by glass panels. However the definition of IfcPlate is material independent and specific material information shall be handled by using IfcAssociatesMaterial to assign a material specification to the IfcPlate.

NOTE Although not necessarily, plates are often add-on parts. This is represented by the IfcRelAggregates decomposition mechanism used to aggregate parts, such as IfcPlate, into a container element, e.g. IfcElementAssembly, or IfcCurtainWall.

An instance IfcPlate should preferably get its geometric representation and material assignment through the type definition by IfcPlateType assigned using the IfcRelDefinesByType relationship. This allows identical plates in a construction to be represented by the same instance of IfcPlateType.

HISTORY New entity in IFC Release 2x2

Property Set Use Definition:

The property sets relating to the IfcPlate are defined by the IfcPropertySet and attached by the IfcRelDefinesByProperties relationship. It is accessible by the inverse IsDefinedBy relationship. The following property set definitions specific to the IfcPlate are part of this IFC release:

Pset_PlateCommon: common property set for all plate occurrences

Containment Use Definitions

The IfcPlate, as any subtype of IfcBuildingElement, may participate in two different containment relationships. The first (and in most implementation scenarios mandatory) relationship is the hierachical spatial containment, the second relationship is the aggregation within an element assembly.

The IfcPlate is placed 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 IfcBuildingStorey being the default container.
The IfcPlate may be aggregated into an element assembly using the objectified relationship IfcRelAggregates, referring to it by its inverse attribute SELF\IfcObjectDefinition.Decomposes. Any subtype of IfcElement can be an element assembly, with IfcElementAssembly as a special focus subtype. In this case, no additional relationship to the spatial hierarchy shall be given (i.e. SELF\IfcElement.ContainedInStructure = NIL), the relationship to the spatial container is handled by the element assembly.

Geometry use definition

The geometric representation of IfcPlate is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are:

Local Placement

The local placement for IfcPlate is defined in its supertype IfcProduct. It is defined by the IfcLocalPlacement, which defines the local coordinate system that is referenced by all geometric representations.

The PlacementRelTo relationship of IfcLocalPlacement shall point (if given) to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.

If the IfcPlate is part of an assembly, the PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the container element, e.g. IfcElementAssembly,

If the relative placement is not used, the absolute placement is defined within the world coordinate system.

Geometric Representations

Currently, the use of 'SweptSolid', 'Clipping', 'Brep' and 'MappedRepresentation' representations is supported. In addition the general representation types 'SurfaceModel' and 'BoundingBox' are allowed. The geometry use definition for 'BoundingBox', 'SurfaceModel' and 'Brep' is explained at IfcBuildingElement.

SweptSolid Representation
The standard geometric representation of IfcPlate is defined using the 'SweptSolid' representation. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

RepresentationIdentifier : 'Body'
RepresentationType : 'SweptSolid'

Clipping Representation
The advanced geometric representation of IfcMember is defined using the 'Clipping' geometry. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

RepresentationIdentifier : 'Body'
RepresentationType : 'Clipping'

MappedRepresentation
In addition to the standard geometric representation of IfcPlate that is defined using the 'SweptSolid' or 'Clipping' geometry, also the 'MappedRepresentation' shall be supported as it allows for reusing the geometry definition of the member type at all occurrences of the same type. The following attribute values for the IfcShapeRepresentation holding this geometric representation shall be used:

RepresentationIdentifier : 'Body'
RepresentationType : 'MappedRepresentation'

The same constraints, as given for the standard 'SweptSolid' and the advanced 'SweptSolid' and 'Clipping' geometric representation, shall apply to the MappedRepresentation of the IfcRepresentationMap.

Use definition for steel members

When using the IfcPlate for steel members in steel construction applications the following additional conventions apply:

Definition by non-geometric properties
Additional non-geometric properties can be specified through the class IfcPropertySet, which is attached to the inverse attribute IfcObject.IsDefinedBy through the objectified relationship IfcRelDefinesByProperties. This allows for attaching country-specific information to structural members.

Decomposition
An instance of IfcPlate can be part of a decomposition through the IfcRelAggregates relationship - both as sub-ordinate or as a super-ordinate component.

If the IfcPlate instance is a sub-ordinate component (i.e. the plate is an add-on part), its local placement shall be relative to that of the super-ordinate instance.
As a super-ordinate component, the sub-ordinates of IfcPlate can be other plates or instances of IfcProxy, or IfcDiscreteAccessory (like IfcFastener).

Position number
The position number is assigned through the attribute IfcElement.Tag

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	A
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[1:1]	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.	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
	IsDecomposedBy	IfcRelDecomposes @RelatingObject	S[0:?]	Reference to the decomposition relationship, that allows this object to be the composition of other objects. An object can be decomposed by several other objects.	X
	Decomposes	IfcRelDecomposes @RelatedObjects	S[0:1]	References to the decomposition relationship, that allows this object to be a part of the decomposition. An object 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	IfcLabel	[0:1]	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
	IsDefinedBy	IfcRelDefines @RelatedObjects	S[0:?]	Set of relationships to type or property (statically or dynamically defined) information that further define the object. In case of type information, the associated IfcTypeObject contains the specific information (or type, or style), that is common to all instances of IfcObject referring to the same type.	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
IfcElement
8	Tag	-		This attribute is out of scope for this model view definition and shall not be set.
	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 Voids Relationship that creates an opening in an element. An element can incorporate zero-to-many openings.	X
	IsConnectionRealization	IfcRelConnectsWithRealizingElements @RealizingElements	S[0:?]	Reference to the connection relationship with realizing element. The relationship then refers to the realizing element which provides the physical manifestation of the connection relationship.	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.	X
IfcBuildingElement
IfcPlate

Definitions applying to AISC Model View

Instance diagram

Concept usage

Properties on Occurrences

The Properties on Occurrences concept applies to this entity as shown in Table 21.

Property
AISC_EM11_Pset_PieceIdentification
AISC_EM11_Pset_ToleranceForLayout
AISC_EM11_Pset_Material
AISC_EM11_Pset_StatusInformation
AISC_EM11_Pset_VersionInformation

Table 21 — IfcPlate Properties on Occurrences

Exchange
Import	O
Export	O

Placement

The Placement concept applies to this entity.

Exchange
Import	R
Export	R

Body Geometry

The Body Geometry concept applies to this entity.

Exchange
Import	R
Export	R

Concept alternates

Body Profile Extruded Area Solid

The Body Profile Extruded Area Solid concept applies to this entity.

Exchange
Import	O
Export	O

Mapped Geometry

The Mapped Geometry concept applies to this entity.

Feature Substraction

The Feature Substraction concept applies to this entity as shown in Table 22.

FeatureObjectType	Description
BoltHole	Represents an instance of Bolt Hole
SlotHole	Represents an instance of a Slot Hole
Cope	Represents an instance of a Cope
Opening	Represents an instance of an Opening
SkewedEnd	Represents an instance of a Skewed End, which has two axis of rotation
WeldPreparation	Represents an instance of a Weld Preparation

Table 22 — IfcPlate Feature Substraction

Exchange
Import	O
Export	O

Material Solid

The Material Solid concept applies to this entity.

Exchange
Import	O
Export	O

Concept inheritance

#	Concept	Model View
IfcPlate
	Properties on Occurrences	AISC Model View
	Placement	AISC Model View
	Body Geometry	AISC Model View
	Feature Substraction	AISC Model View
	Material Solid	AISC Model View

Formal representations

XSD Specification

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

 <xs:complexType name="IfcPlate">

  <xs:complexContent>

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

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcPlate

 SUBTYPE OF (IfcBuildingElement);

END_ENTITY;

 EXPRESS-G diagram

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