1. Faculty of Engineering and Architecture
Session 3
Ontologies in architecture, engineering and
construction (AEC)
Workshop Ontology Modelling
Barcelona, 19-21 December 2011

2. Faculty of Engineering and Architecture
Outline
1. Ontologies in the AEC sector: state of the art (P. Pauwels)
2. Case 1: architectural design information (P. Pauwels)
3. Case 2: energy related data (Alvaro Sicilia, Fàtima Galàn)

3. Faculty of Engineering and Architecture
USE OF ONTOLOGIES IN THE AEC
SECTOR: STATE OF THE ART
3

4. Faculty of Engineering and Architecture
There have always been ontologies,
also in the AEC sector…

5. Faculty of Engineering and Architecture
Google

6. Faculty of Engineering and Architecture
Databases

7. Faculty of Engineering and Architecture
Programming code in UML

8. Faculty of Engineering and Architecture
[1] P. Pauwels, D. Van Deursen, J. De Roo, T. Van Ackere, R. De Meyer, R. Van de Walle, J. Van Campenhout. Three-
dimensional information exchange over the semantic web for the domain of architecture, engineering, and construction.
Artificial Intelligence for Engineering Design, Analysis and Manufacturing 25 (4) 2011, 317-332.

9. Faculty of Engineering and Architecture
AutoCAD

10. Faculty of Engineering and Architecture
3DSMax

11. Faculty of Engineering and Architecture
<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSpy v2010 rel. 2 (http://www.altova.com) by Don Brutzman (Naval Postgraduate School) -->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified"
version="3.1.2">
<!--======================================================================-->
<!-- Public and private schema extension mechanisms -->
<xs:include schemaLocation="x3d-3.1-Web3dExtensionsPublic.xsd"/>
<xs:include schemaLocation="x3d-3.1-Web3dExtensionsPrivate.xsd"/>
[…]
<xs:group name="ComposedGeometryContentModel">
<xs:annotation>
<xs:appinfo>ComposedGeometryContentModel is the child-node content model corresponding to
X3DComposedGeometryNodes. It can contain Color (or ColorRGBA), Coordinate, Normal and TextureCoordinate,
in any order. No more than one instance of these nodes is allowed. Multiple VertexAttribute (FloatVertexAttribute,
Matrix3VertexAttribute, Matrix4VertexAttribute) nodes can also be contained.</xs:appinfo>
<xs:documentation source="http://www.web3d.org/x3d/specifications/ISO-IEC-19775-1.2-X3D-
AbstractSpecification/Part01/components/geometry3D.html#IndexedFaceSet"/>
</xs:annotation>
<xs:choice>
<xs:element ref="FloatVertexAttribute">
<xs:annotation>
<xs:documentation>attrib</xs:documentation>
</xs:annotation>
</xs:element>
<xs:element ref="Matrix3VertexAttribute">
<xs:annotation>
<xs:documentation>attrib</xs:documentation>
</xs:annotation>
</xs:element>
[…]
X3D Schema in XSD / XML
[2] X3D Schema Definition. http://www.web3d.org/specifications/x3d-3.1.xsd.

12. Faculty of Engineering and Architecture
So, what about the BIM
approach?

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17. Faculty of Engineering and Architecture
[3] R. Verstraeten, P. Pauwels, R. De Meyer, W. Meeus, J. Van Campenhout, G. Lateur.
IFC-based calculation of the Flemish energy performance standard.
In: Proceedings of the 7th European Conference on Product and Process Modelling 2008.

18. Faculty of Engineering and Architecture
Current situation in construction industry

19. Faculty of Engineering and Architecture
Current situation in construction industry

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Current situation in construction industry

21. Faculty of Engineering and Architecture
Semantic web technologies:
Let us link all information together
using one common generic language

22. Faculty of Engineering and Architecture
design
[4] Linked Data – Connect Distributed Data across the Web. http://linkeddata.org/ (2011)

23. Faculty of Engineering and Architecture
Just-in-time linking data
?

24. Faculty of Engineering and Architecture
Semantic web stack
[5] Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.

25. Faculty of Engineering and Architecture
RDF graphs
[6] P. Pauwels, D. Van Deursen, R. Verstraeten, J. De Roo, R. De Meyer, R. Van de Walle, J. Van Campenhout. A semantic
rule checking environment for building performance checking. Automation in Construction 20(5) 2011, 506-518.

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Complex rules in an RDF graph
[6] P. Pauwels, D. Van Deursen, R. Verstraeten, J. De Roo, R. De Meyer, R. Van de Walle, J. Van Campenhout. A semantic
rule checking environment for building performance checking. Automation in Construction 20(5) 2011, 506-518.

28. Faculty of Engineering and Architecture
SOAP
Linked PubMed databases Open APIs

29. Faculty of Engineering and Architecture
Parallel descriptions of information :
IFC/RDF + X3D/RDF + STL/RDF
STL/RDF
X3D/RDF
IFC/RDF
[7] P. Pauwels, D. Van Deursen, J. De Roo, T. Van Ackere, R. De Meyer, R. Van de Walle, J. Van Campenhout. Three-
dimensional information exchange over the semantic web for the domain of architecture, engineering, and construction.
Artificial Intelligence for Engineering Design, Analysis and Manufacturing 25 (4) 2011, 317-332.

30. Faculty of Engineering and Architecture
CASE 1: ARCHITECTURAL DESIGN
INFORMATION
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31. Faculty of Engineering and Architecture
Convert existing ontologies
to a semantic web version (OWL)

32. Faculty of Engineering and Architecture
D2R server
[8] C. Bizer, R. Cyganiak. D2R Server – Publishing relational databases on the semantic web.
http://www4.wiwiss.fu-berlin.de/bizer/d2r-server/.

33. Faculty of Engineering and Architecture
IFC-to-RDF
Mapping schema’s:
1. ifcXML to RDF/XML via XSLT transformation
1. Light-weight: conversion can occur
completely on an instance level
2. Time-consuming and prone to errors: it
takes time and concentration to build the
XSLT file
3. Limited expressiveness of RDF/XML
format (no rule functionality)
2. Translate EXPRESS schema to OWL ontology
and use the ontology to build RDF instance
graphs
1. Less prone to errors: once the mapping
between EXPRESS elements and OWL
elements is made, everything goes
smoothly and correctly
2. High expressiveness because of N3
syntax
[9] P. Pauwels, D. Van Deursen, R. Verstraeten, J. De Roo, R. De Meyer, R. Van de Walle, J. Van Campenhout. A semantic
rule checking environment for building performance checking. Automation in Construction 20(5) 2011, 506-518.

34. Faculty of Engineering and Architecture
RDF view on IFC
• IFC specification is written in EXPRESS
ENTITY IfcDoor
SUBTYPE OF ( IfcBuildingElement);
OverallHeight : OPTIONAL IfcPositiveLengthMeasure;
OverallWidth : OPTIONAL IfcPositiveLengthMeasure;
END_ENTITY;
• Two tasks
– automatic transformation of EXPRESS to OWL/RDF
– automatic conversion of IFC to RDF instances

35. Faculty of Engineering and Architecture
Simplified OWL representation of IFC
ENTITY IfcDoor
SUBTYPE OF ( IfcBuildingElement);
OverallHeight : OPTIONAL IfcPositiveLengthMeasure;
OverallWidth : OPTIONAL IfcPositiveLengthMeasure;
END_ENTITY;
TYPE IfcPositiveLengthMeasure = REAL;
END_TYPE;
ifc:IfcDoor
rdfs:subClassOf ifc:IfcBuildingElement;
a owl:Class.
ifc:overallHeight
rdfs:domain ifc:IfcDoor;
rdfs:range xsd:double;
a owl:DatatypeProperty.
ifc:overallWidth
rdfs:domain ifc:IfcDoor;
rdfs:range xsd:double;
a owl:DatatypeProperty.

36. Faculty of Engineering and Architecture
EXPRESS to OWL: challenges
• Name conflicts
– RDF properties are independent of classes
(<> EXPRESS)
– are the semantics still the same?
• Conversion of rules expressed in EXPRESS to N3 rules
ENTITY IfcPixelTexture
Width : IfcInteger;
Height : IfcInteger;
WHERE
WR21 : Width >= 1;
END_ENTITY;
• Conversion of functions expressed in EXPRESS to ???
– built-in functions, N3 rules, ...

37. Faculty of Engineering and Architecture
IFC-to-RDF
Online service that converts
building information in the
Industry Foundation Classes
(IFC) schema into an RDF
graph
[10] MultimediaLab. IFC-to-RDF service. http://ninsuna.elis.ugent.be/IfcRDFService.
[11] MultimediaLab. IFC/RDF SPARQL endpoint. http://ninsuna.elis.ugent.be/SPARQLEndpoint/.

38. @prefix : <http://multimedialab.elis.ugent.be/ontologies/ifc/instances#>.
@prefix ifc: <http://multimedialab.elis.ugent.be/ontologies/ifc/ontology#>.
Faculty of Engineering and Architecture
@prefix list: <http://www.co-ode.org/ontologies/lists/2008/09/11/list.owl#>.
@prefix xsd: <http://www.w3.org/2001/XMLSchema#>.
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
:ifcOrganization_1
ifc:name "Autodesk Revit Architecture 2010"^^xsd:normalizedString;
ifc:theIfcId "1"^^xsd:long;
rdf:type ifc:IfcOrganization.
:ifcApplication_2
ifc:applicationDeveloper :ifcOrganization_1;
ifc:version "2010"^^xsd:normalizedString;
ifc:applicationFullName "Autodesk Revit Architecture 2010"^^xsd:normalizedString;
ifc:applicationIdentifier "Revit"^^xsd:normalizedString;
ifc:theIfcId "2"^^xsd:long;
rdf:type ifc:IfcApplication.
:ifcCartesianPoint_4
ifc:coordinates ( "0.0"^^xsd:double "0.0"^^xsd:double );
ifc:theIfcId "4"^^xsd:long;
rdf:type ifc:IfcCartesianPoint.
:ifcDirection_5
ifc:directionRatios ( "1.0"^^xsd:double "0.0"^^xsd:double "0.0"^^xsd:double );
ifc:theIfcId "5"^^xsd:long;
rdf:type ifc:IfcDirection.
:ifcDirection_10
ifc:directionRatios ( "0.0"^^xsd:double "0.0"^^xsd:double "-1.0"^^xsd:double );
ifc:theIfcId "10"^^xsd:long;
rdf:type ifc:IfcDirection.
:ifcDirection_11
ifc:directionRatios ( "1.0"^^xsd:double "0.0"^^xsd:double );
ifc:theIfcId "11"^^xsd:long;

39. Faculty of Engineering and Architecture
Pubby
OpenLink Virtuoso SPARQL endpoint
[12] R. Cyganiak, C. Bizer. Pubby – A linked data frontend for SPARQL endpoints. http://www4.wiwiss.fu-berlin.de/pubby/.
[13] OpenLink Software. Virtuoso Universal Server. http://virtuoso.openlinksw.com/.

40. Faculty of Engineering and Architecture
…

41. Faculty of Engineering and Architecture
Build new ontologies and new information models

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46. Faculty of Engineering and Architecture
Architectural Information Modelling (AIM)

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[14] P. Pauwels, D. Di Mascio, R. De Meyer, J. Van Campenhout.
About the interpretation of virtual heritage artefacts: case study of the Tower of Books in Ghent, Belgium.
In: Journal on Computing and Cultural Heritage (2012) (submitted).