Lesson from Pieter Pawels on "ifcOWL - an ontology for building data" in the 1st Summer School on Smart Cities and Linked Open Data (LD4SC 2015).

1. ifcOWL
an
ontology
for
building
data
Pieter
Pauwels
Ghent
University

2. WHAT
IS
BIM
/
WHAT
IS
IFC?

3. Building
Informa>on
Modelling

4. ISO
standard
file
format
• Industry
Founda>on
Classes
• Managed
by
BuildingSMART
• Schema
specified
in
EXPRESS
informa>on
modelling
language
• Number
of
versions:
IFC2X2
–
IFC2X3
–
IFC4

5. buildingsmart-­‐tech.org

7. The
EXP
file

8. BUILDING
AN
IFCOWL
ONTOLOGY
FOR
DESCRIBING
BUILDING
DATA

9. implementa>on
proposals
2005-­‐2012
• Diverse
sugges>ons
in
academic
research
to
make
IFC
available
as
an
OWL
ontology
to
allow
the
usage
of
seman>c
web
technologies
Ø Schevers
and
Drogemuller,
2005
Ø Beetz
et
al.,
2009
• General
purpose
ini>a>ve
to
convert
EXPRESS
schemas
and
STEP
file
to
OWL
ontology,
not
focused
on
IFC
Ø Krima
et
al.,
2009(OntoSTEP)
Ø Barbau
et
al.,
2012
(OntoSTEP)
• From
2012
onwards,
increasing
uptake
in
research
and
developments
=>
many
different
ifcOWL
structures
floa>ng
around
• Need
for
formalisa>on
and
standardisa>on
=>
combine
efforts
and
proceed
in
a
more
formalised,
standard
fashion
=>
role
of
standardisa>on
bodies:
W3C,
BuildingSMART

10. Towards
a
recommendable
and
usable
ifcOWL
ontology
• When:
2nd
half
of
2014
• Who:
Pieter
Pauwels
(Ugent)
and
Walter
Terkaj
(ITIA-­‐CNR)
• What:
dis>ll
ONE
recommended
conversion
procedure
for
conver>ng
an
EXPRESS
schema
into
an
OWL
ontology,
based
on
earlier
efforts.
• Results:
– Conversion
procedure
documented
in
ar>cle
manuscript
and
separate
slideshow
– Implemented
in
JAVA
(
hcps://github.com/mmlab/IFC-­‐to-­‐RDF-­‐converter/tree/BS)
and
C++
converter
– Resul>ng
ontologies:
• hcp://linkedbuildingdata.net/resources/IFC4_ADD1.owl
• hcp://linkedbuildingdata.net/resources/IFC2X3_TC1.cl

11. conver>ng
EXPRESS
schema
to
OWL
IFC
Schema
Simple
data
type
Defined
data
type
Aggrega>on
data
type
SET
data
type
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
LIST
&
ARRAY
data
type
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
Constructed
data
type
SELECT
data
type
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
ENUMERATION
data
type
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
En>ty
data
type
Acributes
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
Derive
acr
WHERE
rules
Func>ons
Rules
ifcOWL
Ontology
owl:class
+
owl:DatatypeProperty
restric>on
owl:class
owl:class
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
owl:ObjectProperty
restric>on
on
ifc:hasSet
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
indirect
subclass
of
ifc:List
owl:class
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
owl:unionOf
(
owl:classes
)
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
one
of
(
owl:NamedIndividuals
)
owl:class
-­‐-­‐-­‐-­‐-­‐-­‐-­‐-­‐
object
proper>es
-­‐
-­‐
-­‐
-­‐

12. ifcOWL
ontologies
available
Ifc2x_all_lf.exp
IFC2X2_ADD1.exp
IFC2X2_FINAL.exp
IFC2X2_PLATFORM.exp
IFC2X3_Final.exp
IFC2X3_TC1.exp
IFC4.exp
IFC4_ADD1.exp
not
supported
not
supported
not
supported
not
supported
IFC2X3_Final.owl
/
.cl
IFC2X3_TC1.owl
/
.cl
IFC4.owl
/
.cl
IFC4_ADD1.owl
/
.cl
hcp://www.linkedbuildingdata.net/resources/IFC2X3_Final.cl
hcp://www.linkedbuildingdata.net/resources/IFC2X3_TC1.cl
hcp://www.linkedbuildingdata.net/resources/IFC4.cl
hcp://www.linkedbuildingdata.net/resources/IFC4_ADD1.cl

13. CLASSES
INDIVIDUALS
OJECT
PROPERTIES

14. RESTRICTIONS

15. I
WANT
TO
HAVE
IFCOWL
INDIVIDUALS

16. Op>on
1
–
Manual
modelling
from
scratch
using
an
ontology
editor

17. 1. Not
all
IFC
restric>ons
(rules,
derive
acributes,
func>ons)
available
in
ifcOWL
=>
no
complete
consistency
checking
2. Tedious
and
error-­‐prone
process
limita>ons

18. Op>on
2
–
Automa>c
modelling
from
scratch
using
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);
}

19. 1. Not
all
IFC
restric>ons
(rules,
derive
acributes,
func>ons)
available
in
ifcOWL
=>
no
complete
consistency
checking
2. Need
to
build
modelling
applica>on
anew,
relying
on
a
different
sopware
library
at
the
basis
limita>ons

20. Op>on
3
–
Conversion
of
exis>ng
IFC
SPFF
Files
Free
open
file-­‐to-­‐file
conversion
service:
hcp://smartlab1.elis.ugent.be:8889/IFC-­‐repo/

21. 1. Two
dis>nct
applica>ons,
two
dis>nct
models
-­‐>
versions
can
go
out
of
control
2. The
converter
can
become
a
bocleneck
limita>ons

22. COMMUNITY
EFFORTS

23. Joining
/
combining
ini>a>ves
W3C
LBD
Community
Group
BuildingSMART
LD
Task
Force
linkedbuildingdata.net
www.w3.org/community/lbd/
…
linkedbuildingdata
people
LDAC
event

24. Thank
you
pipauwel.pauwels@ugent.be