help > Opening Native Space FreeSurfer Images
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Jan 3, 2023  05:01 PM | Steven Meisler - Harvard University / MIT
Opening Native Space FreeSurfer Images
Hello,

I am using Surfice v1.0.20211006 (latest at time of writing) on an Apple machine. My goal is to make an image of some tractography bundles within the brain surface, with all files having been produced by FreeSurfer (v7.2). I can import the tracts fine, though as expected they do not align with the pre-loaded template.

However, I cannot figure out how to import my own brain surfaces. The most promising option to me seemed like File --> Open Bilateral (.lh, .rh). When I try this, I am only able to select one file (that is, I could not import lh.curv and rh.curv simultaneously as I expected). Importing either lh.curv or rh.curv results in the following error: 
curv file corrupted: overlay does not match background mesh: 163423 vertices and 326842 triangles :/Users/smeisler/Downloads/sub-START002_ses-post.long.sub-START002/surf/lh.curv

I get the same error with File --> Open

How should I proceed?

Thanks,
Steven
Feb 12, 2023  02:02 AM | tfuh918
RE: Opening Native Space FreeSurfer Images
I am having this same problem. Did you find a solution?
Feb 12, 2023  02:02 PM | Chris Rorden
RE: Opening Native Space FreeSurfer Images
This is a limitation of FreeSurfer, not Surfice

Unfortunately, FreeSurfer uses a spatial transform that is not defined by the GIfTI specification. This causes issues for tools that assume the mesh is a valid GIfTI file (e.g. Surfice, NiiVue, fmriprep). You can apply this transform by using the FreeSurfer tool:
  mris_convert –to-scanner
However, current versions of FreeSurfer apply the transform but retain the transform. Therefore, after this transform is applied the meshes appear correct in GIfTI-compliant tools but incorrect in FreeSurfer. The good news is that the FreeSurfer team has included a flag in the development release that allows FreeSurfer and other tools to determine whether the transform should be applied or not. Once that becomes a stable FreeSurfer release, we can update Surfice to handle these images seamlessly.

For more details see:
  https://github.com/niivue/niivue/issues/416
  https://neurostars.org/t/transform-freesurfer-mesh-coordinates-to-volume-coordinates/23693/2