# "fsaverage" surface generation

**URL:** <https://mne.discourse.group/t/fsaverage-surface-generation/1356>\
**Category:** Mailing List Archive (read-only)\
**Tags:** list-archive\
**Created:** [November 7, 2017, 7:58pm UTC](https://mne.discourse.group/t/fsaverage-surface-generation/1356 "2017-11-07T19:58:47Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\
**Post date:** [November 7, 2017, 7:58pm UTC](https://mne.discourse.group/t/fsaverage-surface-generation/1356/1 "2017-11-07T19:58:47Z")

</div>

Hi,

I'm attempting to scale the "fsaverage" head based on subject-specific  
digitization points, and to create and scale 3 layer BEM that will be  
used to localize EEG data (only). The machines I'm using have Freesurfer  
6.0, and I'm running mne-python in a Python 2 virtual Environment.

When I first load the coregistration GUI, I'm given the option to  
transfer the fsaverage head to my subjects directory, which also copies  
some MNE-specific files over  
([https://github.com/mne-tools/mne-python/tree/master/mne/data/fsaverage](https://github.com/mne-tools/mne-python/tree/master/mne/data/fsaverage)).

If I exit the GUI, and then run:

mne make\_scalp\_surfaces -s fsaverage -n

It seems like it should generate a high-resolution copy of the head. But  
when I load the coreg GUI back up, and toggle the "high resolution head  
option", I see the following:

Low-res head:  
[https://drive.google.com/file/d/10k4PDpLwvERYSAbrLUtum0vDRvXJYLe4/view?usp=sharing](https://drive.google.com/file/d/10k4PDpLwvERYSAbrLUtum0vDRvXJYLe4/view?usp=sharing)

Hi-res head:  
[https://drive.google.com/file/d/11hzLgWYmQXtoeU1J013lRhLsNFnQuzeF/view?usp=sharing](https://drive.google.com/file/d/11hzLgWYmQXtoeU1J013lRhLsNFnQuzeF/view?usp=sharing)

The shapes of the head seem different moreso than just the the face  
distortion, and the fiducial markers, by eye, don't seem to be quite at  
the same anatomical landmarks...even though both heads correspond to  
"fsaverage".

Is it "safe" to ignore this discrepancy, and simply run the watershed  
algorithm and 3-layer BEM construction for fsaverage?

-Lenny