BIM File Format Fun

If you ever thought it was difficult to work with GIS file formats, you haven’t explored the world of BIM. With Cityzenith I’m getting back into converting BIM and it’s making me nogstagic for Esri’s File Geodatabase or LIDAR formats. One of our core features at Cityzenith is drag and drop BIM model import. We’re supporting COLLADA, FBX, IFC, OBJ and CityGML for now but it seems every time I talk with a user they want to import some very proprietary BIM format. I won’t even get into the issues with importing Autodesk’s Revit but look how hard it is for even Safe FME.

The great thing about most of these 3D formats (beyond Revit) is they are relitively open and there are many tools for reading and writing them. But the sheer amount of formats means that you’ve got to plan for these in your software workflows. IFC and FBX do a great job of saving a lot of the BIM data on export while formats such as COLLADA basically drop everything except the structure. Most of the time this isn’t an issue because BIM files have so much data in them that really isn’t important for a planning and development tool such as Cityzenith, but we want to grab much of this to allow our users to perform analysis on building information.

We also want to grab floors of the building and basic structure beyond just the building shell. When we’re integrating IoT feeds into buildings, having the floors or rooms is critically important. IFC is the hope and the failure of openBIM. In an attempt to be everything to everyone, you end up with a bloated format but one that will address all your needs. Being able to programatically pull out floors and rooms of a BIM model requires a ontology for us to work with and IFC sticks to one that we can work with.

But any consultant will tell you, each user(client) has their own unique ontology that you have to work with. Safe Software has been dealing with this for years and has done an amazing job of working with these little idiosyncrasies that enter not only file formats but the models that humans create in them. It’s been really fun getting back into BIM and BIM file formats full time. BIM to GIS (or GIS to BIM) is hard but that challenge and making it simple and repeatable for all users is going to make it very exciting.