Editing Industry Foundation Classes (section)

==File Formats==
{{See also|List of free and open-source software packages#3D|l1=Open-source 3D file formats}}
IFC defines multiple file formats that may be used, supporting various encodings of the same underlying data.<ref>{{cite web |url=https://technical.buildingsmart.org/standards/ifc/ifc-formats/ |title=IFC Formats|publisher=buildingSMART |access-date=2021-12-21 }}</ref>
* IFC-SPF is a text format defined by [[ISO 10303-21]] ("STEP-File"), where each line typically consists of a single object record, and having file extension ".ifc".  This is the most widely used IFC format, having the advantage of compact size yet readable text.
* IFC-XML is an [[XML]] format defined by [[ISO 10303-28]] ("STEP-XML"), having file extension ".ifcXML".  This format is suitable for interoperability with XML tools and exchanging partial building models.  Due to the large size of typical building models, this format is less common in practice.
* IFC-ZIP is a [[ZIP (file format)|ZIP]] compressed format consisting of an embedded IFC-SPF file or IFC-XML file and having file extension ".ifcZIP".
* IFC-Turtle ([[Turtle (syntax)|Terse RDF Triple Language]]) is a textual semantic data format that uses [[Resource Description Framework|RDF]] and is expressed in the ifcOWL ontology.
* IFC-RDF is a XML-based semantic data format that uses [[Resource Description Framework|RDF]] and is expressed in the ifcOWL ontology.
* ifcJSON uses [[JSON]], a modern format often used by web applications.
* ifcHDF uses [[Hierarchical_Data_Format|HDF]] and is based on the [[ISO 10303-26]] standard for STEP data representation in HDF.

IFC-SPF is in [[ASCII]] format which, while human-readable, suffers from common ASCII file issues, in that file-sizes are bloated, files must be read sequentially from start to finish, mid-file extraction is not possible, files are slow to parse, and definitions are non-hierarchical.<ref name="Grabowski">{{cite web |last1=Grabowki |first1=Ralf |title=The Future of IFC: Enabling Partial BIM Model Exchange (June 8, 2020) |url=https://www.upfrontezine.com/2020/06/upf-1058.html |website=Upfront E-zine |access-date=8 June 2020}}</ref> In addition to ifcXML and ifcZIP, modern data formats include RDF/XML or Turtle (using the ifcOWL ontology), ifcJSON ([[JavaScript Object Notation]], broadly available) and ifcHDF5 ([[Hierarchical Data Format]] v5, binary).<ref name="Grabowski"/> In 2020, buildingSmart had two JSON projects underway: ifcJSON v4 (a direct mapping from EXPRESS-based IFC v4) and ifcJSON v5, plus a research project experimenting with turning IFC into a binary format.<ref name="Grabowski"/>