ifcXML Overview

Summary

This section contains all information about the currect ifcXML release, background information about previous ifcXML releases, and development schedule of future ifcXML releases.

NOTE Since the development of IFC4 (and now IFC4 Add1), the ifcXML specification as XML Schema is fully incorporated into the single IFC HTML Documentation package and no longer distributed separately.

Current final releases of ifcXML

ifcXML4add1 - ifcXML for IFC4 Add1
ifcXML4 - ifcXML for IFC4
ifcXML2x3 - ifcXML for IFC2x Edition 3 Technical Corrigendum 1
ifcXML2x2 - ifcXML for IFC2x Edition 2 Addendum 1

ifcXML4 Release

The ifcXML4 release is published as an XML Schema Definition, XSD, derived from the IFC EXPRESS model. The language binding, i.e. the method of how to translate the IFC EXPRESS model into the ifcXML XSD model, follows the international standard ISO 10303-28 "XML representation of EXPRESS schemas and data".

The final ifcXML XSD schema, and the configuration file to generate the XSD schema are now part of the official IFC4 documentation. For the up-to-date ifcXML specifications, see

IFC4 Add1 online documentation, replacing the IFC4 online documentation, see menu "A. Computer Interpretable Listings"

Please note that the configuration settings are mainly of interest to ISO 10303 toolbox providers. ifcXML implementers normally use such toolbox or the fixed content of an ifcXML XSD model. With IFC4 buildingSMART decided to make more extensive use of the configuration capabilities of ISO 10303-28 in order to reduce some of the overhead coming with the default XML schema binding. Accordingly, a new document has been published describing all configuration settings and its meaning for the ifcXML XSD model.

The ifcXML download package includes the following files:

ifcXML XSD model (ifcXML4.xsd) - part of the IFC4 online documentation configuration settings for translating the IFC EXPRESS model to the ifcXML XSD model (ifcXML4_config.xml) - part of the IFC4 online documentation documentation of used configuration settings (ifcXML4_specification_methodology_V1-1.pdf) configuration schema definition being part of the ISO 10303-28 standard (cnf.xsd)

Another change with the new ifcXML schema is that all required definitions are now integrated in the ifcXML XSD model. Thus, it no longer needs a separate schema with common header and general data type definitions.

ifcXML2x3 Release

The ifcXML release is published as an XML Schema Definition, XSD, derived from the IFC EXPRESS model. The language binding, i.e. the method of how to translate the IFC EXPRESS model into the ifcXML XSD model, follows the international standard ISO 10303-28 ed2 "XML representation of EXPRESS schemas and data". The ISO/CD 10303-28ed2 version of 05-04-2004 is used for the language binding.

The ifcXML schema consists of two parts:

ex.xsd - the common schema for all translated EXPRESS models containing the definitions for the header section and the general data types that results from the translation of the EXPRESS data types. It is a part of ISO 10303-28 ed2. IFC2X3.xsd - the IFC2x3 specific unit of serialization, uos, that contains the XSD definitions of all IFC specific classes, relationships, attributes and data types.

configuration.xml - the configuration file chosen for ifcXML2x3 configuration.xsd - the schema definition, being part of ISO 10303-28 ed2

The ifcXML2x3 file has the following name spaces and XSD file locations, that should be used for online validation, see also NameSpace Discussion page:

ex.xsd name space: urn:iso.org:standard:10303:part(28):version(2):xmlschema:common name space alias: ex XSD schema location: http://www.iai-tech.org/ifcXML/IFC2x3/FINAL/ex.xsd IFC2X3.xsd name space: http://www.iai-tech.org/ifcXML/IFC2x3/FINAL name space alias: ifc XSD schema location: http://www.iai-tech.org/ifcXML/IFC2x3/FINAL/IFC2X3.xsd

ifcXML2x2 Release

The final ifcXML release for IFC2x Edition 2 has been published.

download <<

The ifcXML schema consists of two parts:

ex.xsd - the common schema for all translated EXPRESS models containing the definitions for the header section and the general data types that results from the translation of the EXPRESS data types. It is a part of ISO 10303-28 ed2. IFC2X2_FINAL.xsd - the IFC2x2 specific unit of serialization, uos, that contains the XSD definitions of all IFC specific classes, relationships, attributes and data types.

In addition the packages contains configuration files, normally they are not of interest to implementers, since the content is fixed. The configuration files determine the way, how the EXPRESS file was translated into XSD, and refer to the configurable part of ISO 10303-28 ed2. configuration.xml - the configuration file chosen for ifcXML2x2 configuration.xsd - the schema definition, being part of ISO 10303-28 ed2

The ifcXML2x2 file has the following name spaces and XSD file locations, that should be used for online validation, see also name space discussion. ex.xsd name space: urn:iso.org:standard:10303:part(28):version(2):xmlschema:common name space alias: ex XSD schema location: http://www.iai-tech.org/ifcXML/IFC2x2/FINAL/ex.xsd IFC2X2_FINAL.xsd name space: http://www.iai-tech.org/ifcXML/IFC2x2/FINAL name space alias: ifc XSD schema location: http://www.iai-tech.org/ifcXML/IFC2x2/FINAL/IFC2X2_FINAL.xsd

simple ifcXML

The following "simple ifcXML" specifications based on the IFC4 release candidate 4 have been published:

Simple Product Library to publish product catalogues including geometric representations and product properties

The idea of "simple ifcXML" is to provide use case specific IFC model definitions. This enables to reduce complexity and thus to simplify implementation. It also reduces the file size, which is leading to lower resource requirements.

A "simple ifcXML" is not only based on a subset of the entire IFC model, also known as a Model View Definition, but also makes further use of the configuration capabilities of the ISO 10303-28 standard for translating the IFC EXPRESS model into the ifcXML XSD model. In addition to the configuration settings for the entire ifcXML XSD model it mainly adjusts relationships for a more efficient data management.

The specification of a simple ifcXML XSD model is generated with the steps as shown in the figure below.

IFC to simple ifcXML

According to this process a simple ifcXML package shall include the following specifications: Model View Definition (MVD) provided as mvdXML specification, IFC EXPRESS submodel and further documentation including use case definitions and example files ISO 10303-28 configuration settings for translating the IFC EXPRESS submodel to the simple ifcXML XSD model simple ifcXML XSD model