Hi all,

I'm very much a beginner with Freesurfer and I have a little bit of an odd request. I'm currently 3D printing models of participants' brains as a thank-you for participating in our study. All the data has already been processed through recon-all. Our current process is simple - use mris_convert to get from ?h.pial to ?h.stl. (We don't print any of the subcortical structures just for simplicity's sake.) This gives us great models that we can print at a variety of resolutions, and from what I can tell it's the most popular/only method.

The issue is that the models (which are about 3x3x2 in) take 12 to 20 hours each to print and we sometimes print ~7/week According to our 3D printing specialist, it takes so long essentially because they're not hollow and all the interior matter takes a long time. We'd like to be able to print them faster so we're not taking up all the 3D printer time at our library.

Looking at the image below, it seems like the pial surface file (red outline) has a filled interior, at least when converted to .stl. I'm very unfamiliar with programs like MeshLab but our specialist says he's not able to hollow out the interior using any of his 3D printing programs.

So what I need is either a 'hollow' version of the pial surface (or the cortical surface), or perhaps a file that is just the gray matter that can be converted to a .stl file. The ?h.ribbon.mgz files look like they might be a better option but from what I can tell, the mgz files won't convert to stl. (Again, I'm very new to Freesurfer, so any advice on this would be helpful!) I'm also open to ways to solve this in MeshLab if it just won't work in Freesurfer.

Thanks, Lisa [image: Inline image 1]

Faculty Research Assistant Neurocognitive Development Lab University of Maryland, College Park College Park, MD 20742 mdclark@umd.edu