就目前其他的处理IFC数据三种方法相比，ifcXML是当前运用地最少的。这是由于它文件的容量是SPF文件的2-10倍。然而，ifcXML的主要的主要功能不在于取代整个工程的数据交换而是去负责部分的转换、报告、文档资料和查询工作等等，因为这些文件的容量可以算得上是很小的部分。如果SPF文件的容量已经达到50M，那ifcXML恐怕就无能为力了。关于四种方式的基本比较如上图示。
一些XML的工具在处理大容量文件时显得不那么灵活。关键时候，IFC模型应从服务器或者数据库端被读取。某些数据库支持EXPRESS和XSLT直接执行数据的转换。
IfcXML规范建立在Express规范的基础上并且有着更丰富的拓展。XML规范映射的定义（.xsd）会丢失一些集成规则，反向关系和导出属性的约束。一些不符合IfcXML规范的数据(.xsd)不能被全部转换为IFC EXPRESS的格式（.exp）。 XML与IFC的关系
首先，XML是数据转换的语言。很早就有人预言：ifcXML 会在应用软件领域占有一席之地，特别体现在IFC对象模型和以下之间的映射关系：
● 记载项目进度表，产品数据表等描述的文件；
●包含定单，数据信息请求，电子商务交流等描述的消息； ●基于XML诸如GIS对象模型领域的沟通。
IfcXML的描述也被看好对部分模型AEC-FM的提取，传输和合并的操作。部分模型对于协同设计操作是非常重要的。一般来说，完整的建筑模型的传递在CAD环境下都是以SPF为格式的。
IfcXML的实现
建立应用系统的ifcXML输入/输出接口的基本步骤为：
●决定哪些数据需要从软件应用系统读出或写入，确定哪些数据需要转换。和用
户探讨关于他们需要从应用中转进/转出的数据。
●查看IFC模式，看与哪些实体定义相关。
●理解在应用系统中信息是怎么存储的，从应用存储单元存取信息需要什么编程
接口。
●为要转换的数据设计一个应用系统中的数据结构之间的映射表，一列定义存储
单元中和需要从应用存储单元中存取信息的函数调用；第二列定义到ifcXML模式中和需要转换的数据项匹配的元素的Xpath。
●· 为输入/输出编写使用XML解析器的应用代码，用该编程接口来解析XML实
例文件，并按照步骤4中定义的映射表从ifcXML实例文件和应用存储单元中读取或写入信息。
以上的每一个步骤都需要确保所写的应用遵循IFC的实现指南。只要遵循共同的数据传输标准IFC，并通过一个标准的数据接口输入和输出信息，能实现异构系统之间的数据转换和共享。
已有一些应用程序支持ifcXML， 比如EPM Express Data Manager、Eurostep Model Server， XML SPY 2005、Archi CAD等等。
IFC是国际建筑业事实上的标准，对IFC的研究不仅有很好的先进性，而且有足够的适应性，可以灵活的满足各地各企业完全不同的信息化建设目标。IfcXML模式是一个工业标准XSD，利用ifcXML实现数据交换和共享是一个有章可循的过程。IfcXML模型不需要目标服务器来配合工作，一些关系数据库应用系统和服务器可以将XSD当作SQL DDL一样直接读取。
建筑分类体系OmniClass与IFCXML之间的映射
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发布时间：2011-01-19
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文章来源：斯坦福大学
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责任编辑：dpp307
In most industries practitioners use more than one terminology classification class or data model structure. For instance, in the AEC industry, there are a few ontologies to describe the semantics of building models, such as the Industry Foundation Classes (IFC), the CIMsteel Integration Standards (CIS/2), and the OmniClass Construction Classification System. For various model rebuilding and data exchange purposes, comparison and mapping between heterogeneous ontologies in the same industry are often inevitable.
The ontology comparison and mapping problem is commonly performed manually by domain experts, who are familiar with one or more
industry-specific taxonomies. It could be time-consuming, unscalable and inefficient especially if they start from scratch. Automated comparison and mapping based on the ontology structures and the linguistic similarity between concepts are therefore growing in popularity in recent years. This research tries to propose a different approach to achieve ontology mapping by the use of document corpus as a medium for semantic similarity comparison.
Test Case
In the AEC industry nowadays, the urge for Building Information Model (BIM) leads to the establishment of various description and
classification standards to facilitate data exchange. OmniClass and IfcXML by far are two of the most commonly used data models for buildings and constructions. OmniClass, consisting of 15 tables, categorizes elements and concepts in the AEC industry and provides a rich pool of vocabularies practitioners can use in legal documents. It contains a set of object data elements that represent the parts of buildings or processes, and the relevant information about those parts. IfcXML, specialized in modeling CAD models and work process, is frequently used by practitioners to build information-rich product and process models and to act as a data format for interoperability among different software. It is a single XML schema file comprised of concept terms which are highly hierarchically structured and cross-linked. This test case focuses on the mapping between OmniClass and IfcXML.
OmniClass
Main Idea and Implementation
IfcXML
With the intuition that related terms should appear in the same paragraphs or sections , concept comparison and matching by co-occurrence is proposed to map
different sets of terms in heterogeneous ontologies. The number of co-occurrence of two concepts in the corpus reveals the closeness of the two topics and acts as a means to evaluate the relatedness between them.