IfcClassification

IfcClassification

实体定义

IFC分类用于根据共同目的或其拥有的共同特征将物体排列成一个类别或类别。IfcClassification意义上的分类是按层次结构排列的分类学或分类学方案。对象类别与泛化-专业化关系中的其他类别相关。因此，分类中的分类项以树结构组织。

IfcClassification标识分类引用所指的分类系统或来源。每个分类引用可以引用IfcClassification的一个实例。声明的分类系统可以正式发布，也可以是本地定义的信息分类方法。

注：此类正式发布的分类示例为Omniclass、Uniclass、Masterformat或DIN277。

定义和引用分类系统有两种方法：

在数据集中包括分类系统结构：这里包括一个IfcClassificationReference的层次树，该树定义了分类系统，包括分类项目之间的关系。IfcClassificationReference的ReferencedSource属性将分类项链接到父项，父项最终链接到IfcClassification。

通过分类密钥或id引用分类系统：此处，IfcClassificationReference用于指定分类id或密钥作为标识属性，它可以通过ReferencedSource属性直接链接到IFCClassing。

IFC1.5中的历史新实体

IFC 2x4更改属性版本为可选的。属性：描述、位置和引用标记，反向属性添加了引用。

Attribute inheritance

#	Attribute	Type	Cardinality	Description	C
IfcExternalInformation
IfcClassification
1	Source	IfcLabel	[0:1]	Source (or publisher) for this classification. NOTE  that the source of the classification means the person or organization that was the original author or the person or organization currently acting as the publisher.	X
2	Edition	IfcLabel	[0:1]	The edition or version of the classification system from which the classification notation is derived. NOTE  the version labeling system is specific to the classification system.	X
3	EditionDate	IfcDate	[0:1]	The date on which the edition of the classification used became valid. NOTE  The indication of edition may be sufficient to identify the classification source uniquely but the edition date is provided as an optional attribute to enable more precise identification where required.	X
4	Name	IfcLabel	[1:1]	The name or label by which the classification used is normally known. NOTE  Examples of names include CI/SfB, Masterformat, BSAB, Uniclass, STABU, DIN276, DIN277 etc.	X
5	Description	IfcText	[0:1]	Additional description provided for the classification.	X
6	Location	IfcURIReference	[0:1]	Resource identifier or locator, provided as URI, URN or URL, of the classification.	X
7	ReferenceTokens	IfcIdentifier	L[1:?]	The delimiter tokens that are used to mark the boundaries of individual facets (substrings) in a classification reference. This typically applies then the IfcClassification is used in conjuction with IfcClassificationReference's. If only one ReferenceToken is provided, it applies to all boundaries of individual facets, if more than one ReferenceToken are provided, the first token applies to the first boundary, the second token to the second boundary, and the nth token to the nth and any additional boundary. NOTE  Tokens are typically recommended within the classification itself and each token will have a particular role. EXAMPLE 1 To indicate that the facet delimiter used for DIN277-2 reference key "2.1" ("Office rooms") is ".", a single ReferenceToken ['.'] is provided. To indicate that the facet delimiter used for Omniclass Table 13 (space by function) reference key "13-15 11 34 11" ("Office") are "-" and " ", two ReferenceToken's ['-', ' '] are provided. EXAMPLE 2 The use of ReferenceTokens can also be extended to include masks. The use need to be agreed in view definitions or implementer agreements that stipulates a "mask syntax" that should be used.	X
	ClassificationForObjects	IfcRelAssociatesClassification @RelatingClassification	S[0:?]	The classification with which objects are associated.	X
	HasReferences	IfcClassificationReference @ReferencedSource	S[0:?]	The classification references to which the classification applies. It can either be the final classification notation, or an intermediate classification item.	X

 

EXPRESS Specification

ENTITY IfcClassification
 SUBTYPE OF (IfcExternalInformation);
  Source : OPTIONAL IfcLabel;
  Edition : OPTIONAL IfcLabel;
  EditionDate : OPTIONAL IfcDate;
  Name : IfcLabel;
  Description : OPTIONAL IfcText;
  Location : OPTIONAL IfcURIReference;
  ReferenceTokens : OPTIONAL LIST [1:?] OF IfcIdentifier;
 INVERSE
  ClassificationForObjects : SET OF IfcRelAssociatesClassification FOR RelatingClassification;
  HasReferences : SET OF IfcClassificationReference FOR ReferencedSource;
END_ENTITY;

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