xBIM, an Open Source .NET Toolbox for BIM development

While answering a LinkedIn discussion on Open Source BIM, I stumbled upon the open xBIM toolkit. Apparently, they use the "openbim" domain name, and seem to be related to the openBIM initiative by BuildingSmart and some software companies.

It is not an end-user program, but a software developer toolkit, written for the .NET framework so it should be supported on Windows, inside .NET-supporting applications such as Revit or AutoCAD. In theory, it might also be usable using the Mono framework (an Open Source implementation of the .NET framework that also runs on other platforms, such as Linux or OSX).

It is hosted on codeplex (http://xbim.codeplex.com) which is managed by Microsoft and relies on Open CASCADE for 3D modelling and visualisation.

It has a CDDL license, which is comparable (but not identical) to the LGPL license, which does allow commercial usage, unlike the more stringent GPL license.

The toolkit can help you to write custom software, requiring IFC reading, but it also supports creating BIM models and has geometric operations supported.

You can download a precompiled IFC viewer, but inside the sources, there is also an iOS project for iPhone/iPad.