IFCtoLBD

Version 2.44.0 Free for all of us, forever.

The IFCtoLBD converter transforms Industry Foundation Classes (IFC) files in STEP format into Resource Description Framework (RDF) triples. These RDF triples adhere to the ontologies created by the World Wide Web Consortium (W3C) Linked Building Data Community Group (W3C LBD-CG: https://github.com/w3c-lbd-cg/).

What is IFC?

IFC is a vendor-neutral data format created by buildingSMART. It helps different software in architecture, engineering, and construction (AEC) work together by sharing detailed information about building parts and their connections. You can find sample models here: buildingSMART/Sample-Test-Files. Tools like Solibri Anywhere, BIMcollab ZOOM, FZKViewer, Tekla BIMsight, or BIM Vision can be used to view the files.

What is RDF?

RDF is a web standard by the W3C. It organizes data into triples (subject, predicate, object) to make it easy to share and reuse information across different applications and combine large datasets from various sources. (see Verborgh, The Semantic Web & Linked Data)

Proceedings of the 6th Linked Data in Architecture and Construction Workshop: The IFC to Linked Building Data Converter - Current Status.

It is recommended to use OpenJDK 21 (it is the modt current Long-Term Support version). Java 17 is supported. OpenJava can be downloaded from (https://docs.microsoft.com/en-us/java/openjdk/download). On a Windows system, download the MSI file that matches your processor type (usually x64 aka Intel), and run it to install Java.

Precompiled binaries

Precompiled applications are available in the published release. https://github.com/jyrkioraskari/IFCtoLBD/releases

• Desktop application: IFCtoLBD-Desktop Use Java 21 for compiling the converter and the desktop app. For the OpenAPI interface, it is recommended to use Java 21.

These are runnable JAR files. If the Java installation is fine, the file can be run by clicking it. When converting large files, run.bat can be used. It is also faster since it allows the program to use more memory for the calculation.

Also, Windows 10/11 installations are available. The zip files contain script files to run the program neatly in the windows operating system.

If the program does not start, try the following command at the command line: java -jar IFCtoLBD-Desktop.jar.

Source Code Documentation

Javadoc

Java programming examples can be found here .

The desktop user interface was created using Java FXML, a scripting language defining the user interface in Java applications. You can download the editor from Gluon Scene Builder (see https://gluonhq.com/products/scene-builder/). In the editor, import the org.openjfx:javafx-graphics and org.openjfx:javafx-controls libraries to get the editor working using the library manager.

Compiling the code

The converter can be compiled using Maven and the Java JDK. Maven is a build automation tool for managing a project’s build. You can download Maven from Apache Maven from https://maven.apache.org/download.cgi.

First, make sure that the JAVA_HOME environment variable point to the JAVA JDK directory. JRE is not enough. Then run the following commands:

• In Eclipse, select first Maven Update project for all projects.

  
  cd IFCtoRDF
  call mvn clean install
  cd ..

cd IFCtoLBD_Geometry call mvn clean install cd ..

cd IFCtoLBD call mvn clean install cd ..

cd IFCtoLBD_Desktop call mvn clean install cd ..

cd IFCtoLBD_OpenAPI call mvn clean install call mvn enunciate:docs install cd ..

When done as shown above by using the command line, copy the files in your app folder  <app>  (can be any) and run the conversion.

copy IFCtoRDF/target/ifc-to-lbd--jar-with-dependencies.jar copy IFCtoLBD_Geometry/target/ifc_to_lbd_geometry-.jar copy IFCtoLBD/ifc-to-lbd-*-jar-with-dependencies.jar copy cd

java -cp * org.linkedbuildingdata.ifc2lbd.IFCtoLBDConverter http://lbd.example.com/ output.ttl 2

-  Note: If you have problems compiling the sources, remove the module-info.java files (they expect to find the JAR files of the Maven-referred libraries of older Java versions). 

OLD instruction was:

cd IFCtoLBD_OpenAPI call mvn clean install set MAVEN_OPTS=--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED call mvn enunciate:docs install cd ..

Then, the best way to create a runnable [Java 19] (https://jdk.java.net/19/) program is to 
1. Use an Eclipse (https://www.eclipse.org/) installation,
2. Open org.linkedbuildingdata.ifc2lbd.Main class on the Eclipse editor
3. Select from the menu /Run/Run
4. Select the /File/Export:Java/Runnabe Jar file/Next
5. Launch configuration: -Select the created Main runtime configuration-, Package resource libraries into generated JAR
6. Select destination file and Finish.

An example command line usage of the program is:

java -jar IFCtoLBD.jar Duplex_A_20110505.ifc http://uribase out.ttl

## Maven
The Maven library was published on the 16th of January, 2024.  

## IFCtoLBD Python Implementation

The example implementation can be found in the IFCtoLBD_Python  subfolder

Installation:

pip install JPype1 pip install rdflib

!/usr/bin/env python3

import pprint

import jpype from rdflib import Graph, Literal, RDF, URIRef

Enable Java imports

import jpype.imports

Pull in types

from jpype.types import *

jpype.startJVM(classpath=['jars/*'])

IFCtoLBDConverter = jpype.JClass("org.linkedbuildingdata.ifc2lbd.IFCtoLBDConverter")

Convert the IFC file into LBD level 3 model

lbdconverter = IFCtoLBDConverter("https://example.domain.de/", 3)

model = lbdconverter.convert("Duplex_A_20110505.ifc"); statements = model.listStatements();

g = Graph()

Copy triples to the Python rdflib library

Apache Jena operations:

-------------------

while statements.hasNext(): triple = statements.next() rdf_subject = URIRef(triple.getSubject().toString()) rdf_predicate = URIRef(triple.getPredicate().toString()) if triple.getObject().isLiteral(): rdf_object = Literal(triple.getObject().toString()) else: rdf_object = URIRef(triple.getObject().toString()) g.add((rdf_subject, rdf_predicate, rdf_object))

rdflib operations:

-------------------

for stmt in g: pprint.pprint(stmt) jpype.shutdownJVM()

More Python examples and detailed description can be found 
[here ](/IFCtoLBD_Python/examples.md).

## Docker for the Open API interface

Install Docker Desktop:  https://www.docker.com/get-started

Command-line commands needed to start the server at your computer;

docker pull jyrkioraskari/ifc2lbdopenapi:latest

docker container run -it --publish 8081:8080 jyrkioraskari/ifc2lbdopenapi

Then the software can be accessed from the local web address:
http://localhost:8081/IFCtoLBD_OpenAPI

## Command line usage

Usage: IFCtoLBD_CLI [-bhpV] [-be] [--hasGeolocation] [--hasGeometry] [--hasSeparateBuildingElementsModel] [--hasSeparatePropertiesModel] [--hasTriG] [--hasUnits] [--ifcOWL] [-l=] [-t=] [-u=]