# bad skin (head shape) surface model in mne.gui.coregistration **URL:** \ **Category:** Support & Discussions\ **Created:** [May 7, 2024, 9:17pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766 "2024-05-07T21:17:58Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![gkirk](https://avatars.discourse-cdn.com/v4/letter/g/b38774/32.png) [@gkirk](https://mne.discourse.group/u/gkirk)\ **Post date:** [May 7, 2024, 9:17pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/1 "2024-05-07T21:17:58Z")
Platform macOS-12.7.3-x86\_64-i386-64bit Python 3.11.5 | packaged by conda-forge | (main, Aug 27 2023, 03:35:23) [Clang 15.0.7] Executable /Applications/.mne-python/bin/python CPU i386 (4 cores) Memory 8.0 GB mne 1.6.0 simply running mne.gui.coregistration() with SUBJECTS\_DIR set is sufficient to get the coreg gui to pop up with the ![face](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/e/e66933a6972e023484ba06232656fabf151338e8.jpeg) ---
**Author:** ![gkirk](https://avatars.discourse-cdn.com/v4/letter/g/b38774/32.png) [@gkirk](https://mne.discourse.group/u/gkirk)\ **Post date:** [May 7, 2024, 9:23pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/2 "2024-05-07T21:23:01Z")
my message was not finished, as you can see the mri head shape/skin surface is very blurred and inacurate, not sufficient to accurately place the fiducials. the mri is of good quality as is the freesurfer recon and the bem surfaces. The mri is from an MPnRAGE sequence and so the distribution and overall intensity levels may not be the usual. It seems a threshold problem ? would not want to rerun the watershed as the bem surfaces are quite good. how to fix ? thanks for any help greg ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 7, 2024, 9:57pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/3 "2024-05-07T21:57:42Z")
Can you try passing `head_high_res=True` to the `coregistration()` function? ---
**Author:** ![gkirk](https://avatars.discourse-cdn.com/v4/letter/g/b38774/32.png) [@gkirk](https://mne.discourse.group/u/gkirk)\ **Post date:** [May 7, 2024, 10:10pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/4 "2024-05-07T22:10:30Z")
that was quick, ill try as soon as i can and get back thanks greg ---
**Author:** ![gkirk](https://avatars.discourse-cdn.com/v4/letter/g/b38774/32.png) [@gkirk](https://mne.discourse.group/u/gkirk)\ **Post date:** [May 8, 2024, 4:56pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/5 "2024-05-08T16:56:15Z")
> [@richard](#): > > `head_high_res=True` Hi Richard, I added head\_high\_res=True and it had no effect, also it might be informative to tell you that when the loading is done the screen shows flat gray and when I scroll the head opacity all the way to the right at the very last bit the mri blob pops out of the gray background, so it seems the range is not as expected ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 8, 2024, 5:16pm UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/6 "2024-05-08T17:16:59Z")
@larsoner Any idea what might be happening here? ---
**Author:** ![larsoner](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/larsoner/32/3_2.png) [@larsoner](https://mne.discourse.group/u/larsoner)\ **Post date:** [May 14, 2024, 11:24am UTC](https://mne.discourse.group/t/bad-skin-head-shape-surface-model-in-mne-gui-coregistration/8766/7 "2024-05-14T11:24:44Z")
IIRC `head_high_res=True` will try to use the high res head surface but won’t if it doesn’t exist – it might just fall back to using the one from the watershed BEM (which it looks like it’s using). Do you have `$SUBJECTS_DIR/$SUBJECT/surf/lh.seghead`? If not runninng `mne make_scalp_surfaces` or similar should create it