Summer School LD4SC 2015 - ifcOWL introduction
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Transcript of Summer School LD4SC 2015 - ifcOWL introduction
ISO standard file format
• Industry Foundation Classes• Managed by BuildingSMART• Schema specified in EXPRESS information
modelling language• Number of versions: IFC2X2 – IFC2X3 – IFC4
Towards a recommendable and usable ifcOWL ontology
• When: 2nd half of 2014 • Who: Pieter Pauwels (Ugent) and Walter Terkaj (ITIA-CNR)• What: distill ONE recommended conversion procedure for converting an
EXPRESS schema into an OWL ontology, based on earlier efforts.• Results:
– Conversion procedure documented in article manuscript and separate slideshow
– Implemented in JAVA (https://github.com/mmlab/IFC-to-RDF-converter/tree/BS) and C++ converter
– Resulting ontologies:• http://linkedbuildingdata.net/resources/IFC4_ADD1.owl• http://linkedbuildingdata.net/resources/IFC2X3_TC1.ttl
converting EXPRESS schema to OWLIFC
Schema
Simple data type
Defined data type
Aggregation data typeSET data type --------
LIST & ARRAY data type --------
Constructed data typeSELECT data type --------
ENUMERATION data type --------
Entity data typeAttributes --------
Derive attrWHERE rules
FunctionsRules
ifcOWLOntology
owl:class + owl:DatatypeProperty restriction
owl:class
owl:class-------- owl:ObjectProperty restriction on ifc:hasSet-------- indirect subclass of ifc:List
owl:class-------- owl:unionOf ( owl:classes )-------- one of ( owl:NamedIndividuals )
owl:class-------- object properties
----
More details
in separate
presentation
ifcOWL ontologies available
Ifc2x_all_lf.expIFC2X2_ADD1.expIFC2X2_FINAL.exp
IFC2X2_PLATFORM.expIFC2X3_Final.expIFC2X3_TC1.exp
IFC4.expIFC4_ADD1.exp
not supportednot supportednot supportednot supportedIFC2X3_Final.owl / .ttlIFC2X3_TC1.owl / .ttlIFC4.owl / .ttlIFC4_ADD1.owl / .ttl
http://www.linkedbuildingdata.net/resources/IFC2X3_Final.ttlhttp://www.linkedbuildingdata.net/resources/IFC2X3_TC1.ttlhttp://www.linkedbuildingdata.net/resources/IFC4.ttlhttp://www.linkedbuildingdata.net/resources/IFC4_ADD1.ttl
1. Not all IFC restrictions (rules, derive attributes, functions) available in ifcOWL => no complete consistency checking
2. Tedious and error-prone process
limitations
Option 2 – Automatic modelling from scratchusing APIs
im = ModelFactory.createDefaultModel();im.setNsPrefix("ifcowl", ontNS);im.setNsPrefix("inst", baseURI);for (int i = 0; i < inst.getList().size(); i++) {
OntClass cl = ontModel.getOntClass(ontNS + typeName);Resource r = im.createResource(baseURI + typeName + "_" + inst.getLine_num(), cl);
}
1. Not all IFC restrictions (rules, derive attributes, functions) available in ifcOWL => no complete consistency checking
2. Need to build modelling application anew, relying on a different software library at the basis
limitations
Option 3 – Conversion of existing IFC SPFF Files
Free open file-to-file conversion service: http://smartlab1.elis.ugent.be:8889/IFC-repo/
1. Two distinct applications, two distinct models -> versions can go out of control2. The converter can become a bottleneck
limitations
Joining / combining initiatives
W3C LBD Community Group BuildingSMART LD Task Force
linkedbuildingdata.net
www.w3.org/community/lbd/
…
linkedbuildingdata people
LDAC event