xBIM is extensible because:
- It is open-source. The source codes are available for anybody who wants to participate in the project, to extend and add more functionality to the codes.
- It uses Extension Methods (a feature in C#, the programming language which xBIM was written in). Extension Methods allow existing classes to be extended without relying on inheritance or having to change the class's source code. This means that it is possible and easy to add new methods into the existing classes.
- It has a layered architecture allowing you to build your own behaviour and business objects on top of IFC entities whilst maintaining 100% IFC compatibility with the standard