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.