Open Source IFC Frameworks : some experiences

I have been looking at programming Frameworks for IFC (Industry Foundation Classes), the open standard to exchange Building Information Models. I assume you are at least aware of what they are and what they contain...

While most commercial BIM software currently exports and opens IFC documents, I was interested to learn about actually doing something directly with these files, e.g. analyzing and visualizing or even generating them.

There are a few free IFC viewers available. Tekla BIMsight and Solibri Viewer are both recommended (the latter even cross-platform). But they are closed and can not be adapted for other purposes. However, I also read about a few interesting Open Source projects for creating and opening IFC files.
In the next posts, I will discuss some of them into more detail and try to have them running/compiled on my computer. I discussed BIMserver in an older post.

But first some overall thoughts.

  • Large class libraries: IFC contains a large list of classes. Most frameworks generate C++ or Java classes from the IFC schema files, which is obviously the smart thing to do. Certainly when things do not work well, as you can alter the generation procedure and 500+ classes are updated.
  • Viewers: in most cases, people start with viewing (or parsing) IFC files, to visualize them as lists or 3D models. However, when thinking about generative architecture and procedural design, it would be nice to have model generators too. Open Toolkits might be a way to start supporting them.
  • Cross-platform or not? The examples I found are either C++ or Java. The Java libraries should work on all platforms, whereas for the C++ libraries it depends. The class libraries themselves are commonly platform agnostic,  although many use recent libraries or even newer language constructs that are not always supported everywhere. The viewers are commonly using external libraries and they are not always cross-platform (although many are). As most BIM development seems to occur on Windows machines, I am particularly wary about having it supported on OSX as well. Usually, when Windows is supported, the next platform that is attempted is Linux, and in many cases this is available. But compilation on OSX is usually left at volunteers. So I will try to see if I can help a bit.



Comments

  1. B-Processor is Open Source BIM that is begin developed by an academic team at Arhus School of Architecture in Denmark. To my understanding, they do not support IFC files.

    http://b-processor.dk/

    ifcBrowser, as part of the development around ifcEngineDLL at TNO (Netherlands), is freely available for non-commercial use and source code examples of integration in custom programs is provided, but the ifcEngine is a Windows-only library for linking in your own software and is NOT Open Source at all.

    http://www.ifcbrowser.com/ifcengineviewer.html
    http://www.ifcbrowser.com/ifcenginedll.html

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  2. Other is uberviewer (GPL licence) You can see it in osbim.org

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  3. Uberviewer seems to be a Windows-only MFC program, that uses the non-Open Source IFCEngine.dll.

    While it is licensed as GPL, I'm not sure that it can legally be so.

    It contains MFC-snippets from the Visual Studio App-Wizard, containing copyright claims from Microsoft.

    It links against a non-Open Source (but free) library, that is not distributed as Source Code but in library (binary) form only.

    So while I am supportive of all Open Source BIM efforts, I have doubts about the mixture of licenses in this work.

    And I can not use it inside OSX.

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  4. The IFC Engine DLL is indeed a commercial application and source code is not available for free.

    However it is cross platform with also versions for Linux (not yet for MAC) and all source code is available for a fee.

    For commercial companies this gives the benefit of having access to all source code and being able to update/use (parts of) it without the requirement to add it to the community.

    The examples have free source in the sence that enyone can use them without limitation. Late binding enables use for VB, VB.NET, C/C++, C#, Delphi, JAVA etc. The use of SDAI as an interface should make it possible (for the non geometry part) to exchange the IFC Engine DLL with any other toolbox that supports SDAI.

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  5. Update:

    BIMServer is getting a new IFC Engine (ifcOpenShell) which is a drop-in replacement for the closed -source IFC-Engine in version 1.0. Sounds like this one is clean

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  6. I heard about it and would love to see this succeed, to get a complete Open Source solution (or platform, as BIMserver is more and more becoming).

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