IfcBuildingElementProxy

实体定义

IfcBuildingElementProxy是一个代理定义，它提供与IfcBuildingElement子类型相同的功能，但不具有特定类型建筑图元的预定义含义。

 

代理也可以用作空间占位符或规定，以后可能会被特殊类型的元素所取代。

 

代理对象的一种用途是提供空隙，即某些工程功能要求特定体积的空间，这些空间可能随后被接受或拒绝，如果接受，则可能转换为建筑图元内的空隙，如墙洞口或楼板洞口。无效准备金作为一个IfcBuildingElementProxy进行交换，其预定义类型为ProvisionForVoid。

 

IfcBuildingElementProxy的其他用途包括：

 

IfcBuildingElementProxy可用于交换当前规范尚未提供语义定义的特殊类型的建筑图元。

IfcBuildingElementProxy还可用于表示参与应用程序无法提供语义定义的建筑图元。

IFC2x中增加的新实体。

如果更改，则属性CompositionType已替换为预定义类型，该类型是枚举数的超集。

 

Formal Propositions

Rule	Description
HasObjectName	建筑图元代理声明名称属性。
CorrectPredefinedType	PredefinedType属性未设置（例如，因为关联了IfcBuildingElementProxyType），或者如果PredefinedType设置为USERDEFINED，则应提供继承的属性ObjectType。
CorrectTypeAssigned	没有关联的建筑图元代理类型对象，即未提供IsTypedBy反向关系，或者关联的类型对象必须为IfcBuildingElementProxyType类型。

 

 

 

 

 

 

 

 

 

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
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
	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.	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.	X
	HasProjections	IfcRelProjectsElement @RelatingElement	S[0:?]	Projection relationship that adds a feature (using a Boolean union) to the IfcBuildingElement.	X
	ReferencedInStructures	IfcRelReferencedInSpatialStructure @RelatedElements	S[0:?]	Reference relationship to the spatial structure element, to which the element is additionally associated. This relationship may not be hierarchical, an element may be referenced by zero, one or many spatial structure elements.	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
IfcBuildingElement
IfcBuildingElementProxy
9	PredefinedType	IfcBuildingElementProxyTypeEnum	[0:1]		X

 

 

EXPRESS Specification

ENTITY IfcBuildingElementProxy
 SUBTYPE OF (IfcBuildingElement);
  PredefinedType : OPTIONAL IfcBuildingElementProxyTypeEnum;
 WHERE
  HasObjectName : EXISTS(SELF\IfcRoot.Name);
  CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcBuildingElementProxyTypeEnum.USERDEFINED) OR ((PredefinedType = IfcBuildingElementProxyTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
  CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR ('IFCSHAREDBLDGELEMENTS.IFCBUILDINGELEMENTPROXYTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));
END_ENTITY;

 

 

##################################