What is openBIM?

Getting familiar with Building Information Modelling means coming to grips with a host of new terms and acronyms. This can be pretty frustrating at first, however, with a basic understanding things start to fall into place. This video series is designed to presents openBIM concepts in simple language.

So, let’s start at the beginning: what is openBIM?

openBIM simply means working with BIM using open Standards.

Well, what are open Standards?

Let me give an analogy explain.
To write a report you typically use a word processing application. Maybe, Microsoft Word or Apple Pages.

Once the report is complete, you probably want to share it with your audience. Typically, you don’t send out your reports as a native file, you usually publish a PDF copy. There are a number of reasons for this:
Firstly, if you send a native file, anyone can make changes to your document without you knowing.

Secondly, the native files are proprietary, or closed, formats. This means the receiver needs to have the same application, or a compatible application, to view them.

If you issue a PDF, on the other hand, the document can be viewed with a simple PDF viewer. PDF is an open standard. It is a lightweight file, but still has a lot of functionality. The recipient can view the document, search for words, add comments or markups but they cannot change the original text.

This PDF workflow is comparable to openBIM.
In BIM, we start by creating a model using a commercial modelling software. Here we are working in a native, or proprietary, format.

At some stage we want to share our model with the project team. If we issue the native model, the receiving party must have the same or compatible software to view it. They can also make changes to the model without our knowing. However, if we publish the model in an open exchange format, like IFC, the model data is freely viewable – measurable and usable. But the model content is protected. Changes cannot be made in an IFC file. They are made back in the original modelling software.

So, let’s recap.
Creating model data in a native format is called nativeBIM. If we exchange this model data with an open standard, such as IFC, then we are in openBIM.
But, is there a closedBIM?

Some people refer to working in a native file format as closedBIM, rather than nativeBIM. This is a little misleading, as it suggests something counter to openBIM. In fact, nativeBIM is the basis for openBIM. You can only start an openBIM process by creating a model in a native format. You don’t create models in IFC, you export them to IFC.

And at any stage in a nativeBIM process you can exchange data with open standards and thereby start an openBIM workflow.
The term closedBIM, should really only be used to describe a scenario where openBIM Standards are intentionally excluded. For example, where file exchange is exclusively in a native format.


 Mark Baldwin

  (10 articles)

Australian architect and BIM-specialist. I am drawn to the simple, the pragmatic and the innovative. BIM – the digitalisation of our construction industry – must be all of these things.