A free/opensource workflow from CT scan to FEA

I’ve spent quite a bit of time this year trying to find a good workflow for carrying out finite element analysis (FEA) using only free software. I think I’ve finally got a workflow that works.

Disclaimer: FEA is way more complex than just making colourful stress maps. Whilst the info on this page gives you a workflow, you still need to put in the research hours to figure out what kind of mesh you want, what material properties, and what loads you should use!

CT Data to model

I’ve previously given a full workflow for 3D Slicer, from CT scan to 3D print. The same principle applies. Here, I’ve used ORS Dragonfly, which isn’t open source but is free for non-commercial research. I really like Dragonfly, mainly because of it’s nice renderer, but also because it’s just easier to use the Slicer, in my opinion. You can use anything though, and I‘ve previously written a list of free CT segmentation software packages that you might find useful.

After getting out a model, we need to make sure it’s manifold (watertight), and oriented in such a way that applying loads and constraints is simple (i.e. aligning the directions of forces with world axes). To do this, I used Blender. I used the voxel remesher and 3d print add on to make sure the mesh was watertight but still retained the detail:

What I don’t show in the above video is that I then used the quadriflow remesher to get face count down to 10,000, just so the model was small enough to import and run in the FEA software in a reasonable amount of time.

To carry out the FEA I used FEBio Studio. This is an all-in-one freely available software that can mesh and run the analysis. Again, I wizzed through with not particularly well thought out meshing and materials/loads – if you want to do serious FEA you’ll need to spend plenty of time figuring out what are the best parameters.

And there we are. Total time taken over the three videos is about 12 minutes, from raw CT scan data to FEA results.