IfcStructuralSurfaceMember

Item	Change	Description
IFC2x3 to IFC4
IfcStructuralSurfaceMember
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
PredefinedType	MODIFIED	Type changed from IfcStructuralSurfaceTypeEnum to IfcStructuralSurfaceMemberTypeEnum.

#	Attribute	Type	Cardinality	Description	C
8	PredefinedType	IfcStructuralSurfaceMemberTypeEnum	[1:1]	Type of member with respect to its load carrying behavior in this analysis idealization.	X
9	Thickness	IfcPositiveLengthMeasure	[0:1]	Defines the typically understood thickness of the structural surface member, measured normal to its reference surface.	X

Rule	Description
HasObjectType	The attribute ObjectType shall be given if the predefined type is set to USERDEFINED.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
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).	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).	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.	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).	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	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
	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.	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.	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.	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
IfcStructuralItem
	AssignedStructuralActivity	IfcRelConnectsStructuralActivity @RelatingElement	S[0:?]	Inverse relationship to all structural activities (i.e. to actions or reactions) which are assigned to this structural member.	X
IfcStructuralMember
	ConnectedBy	IfcRelConnectsStructuralMember @RelatingStructuralMember	S[0:?]	Inverse relationship to all structural connections (i.e. to supports or connecting elements) which are defined for this structural member.	X
IfcStructuralSurfaceMember
8	PredefinedType	IfcStructuralSurfaceMemberTypeEnum	[1:1]	Type of member with respect to its load carrying behavior in this analysis idealization.	X
9	Thickness	IfcPositiveLengthMeasure	[0:1]	Defines the typically understood thickness of the structural surface member, measured normal to its reference surface.	X

Definitions applying to Common Use Definitions

Instance diagram

Concept usage

Material Layer Set Usage

The Material Layer Set Usage concept applies to this entity.

The material of direct instances IfcStructuralSurfaceMember (in contrast to instances of the subtype IfcStructuralSurfaceMemberVarying) is defined by IfcMaterialLayerSetUsage and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship.

The material is specified minimally by a name which corresponds with an agreed upon standardized structural material designation. An external reference to the source which specifies the material designation should be provided. Alternatively, structural material properties may be provided by means of IfcMaterialProperties.

In the absense of material layer set usage, direct instances of IfcStructuralSurfaceMember are assumed to be located centrically relative to their reference surface. Their depth is provided in the attribute Thickness.

Reference Topology

The Reference Topology concept applies to this entity as shown in Table 638.

Topology
IfcFaceSurface

Table 638 — IfcStructuralSurfaceMember Reference Topology

Direct instances of IfcStructuralSurfaceMember shall have a topology representation which consists of one IfcFaceSurface, representing the reference surface of the surface member. See definitions at IfcStructuralItem for further specifications.

The local coordinate system is established by the reference surface given by topology representation.

Structural Connectivity

The Structural Connectivity concept applies to this entity as shown in Table 639.

StructuralConnection	Description
IfcStructuralCurveConnection	Connections to curve members along edge(s) of surface.
IfcStructuralSurfaceConnection	Connections to surface members within face(s) of surface.

Table 639 — IfcStructuralSurfaceMember Structural Connectivity

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Common Use Definitions
	Revision Control	Common Use Definitions
IfcObject
	Object Occurrence Predefined Type	Common Use Definitions
IfcStructuralSurfaceMember
	Material Layer Set Usage	Common Use Definitions
	Reference Topology	Common Use Definitions
	Structural Connectivity	Common Use Definitions

Formal representations

XSD Specification

 <xs:element name="IfcStructuralSurfaceMember" type="ifc:IfcStructuralSurfaceMember" substitutionGroup="ifc:IfcStructuralMember" nillable="true"/>

 <xs:complexType name="IfcStructuralSurfaceMember">

  <xs:complexContent>

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

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

    <xs:attribute name="Thickness" type="ifc:IfcPositiveLengthMeasure" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcStructuralSurfaceMember

 SUPERTYPE OF(IfcStructuralSurfaceMemberVarying)

 SUBTYPE OF (IfcStructuralMember);

  PredefinedType : IfcStructuralSurfaceMemberTypeEnum;

  Thickness : OPTIONAL IfcPositiveLengthMeasure;

 WHERE

  HasObjectType : (PredefinedType <> IfcStructuralSurfaceMemberTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);
END_ENTITY;

 EXPRESS-G diagram

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	Structural Surface Member

IfcStructuralSurfaceMember

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to Common Use Definitions

Formal representations