# Fixing inner/outer skull surfaces

**URL:** <https://mne.discourse.group/t/fixing-inner-outer-skull-surfaces/7614>\
**Category:** Support & Discussions\
**Created:** [October 5, 2023, 9:40am UTC](https://mne.discourse.group/t/fixing-inner-outer-skull-surfaces/7614 "2023-10-05T09:40:20Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![nmrogalinski](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/nmrogalinski/32/3077_2.png) [@nmrogalinski](https://mne.discourse.group/u/nmrogalinski)\
**Post date:** [October 5, 2023, 9:40am UTC](https://mne.discourse.group/t/fixing-inner-outer-skull-surfaces/7614/1 "2023-10-05T09:40:20Z")

</div>

- MNE version:1.3.1
- operating system: Linux RedHat7

Hello,

I am having some trouble with getting my inner skull surface to fit within my outer skull surface. The error comes when I run this line of code:

```python
model = mne.make_bem_model(subject = str(subjid), ico=4, conductivity = (0.3, 0.006, 0.3))

```

Just before I get this error, I am able to run the following:

```python
mne.bem.make_scalp_surfaces(subject = str(subjid), subjects_dir=subjects_dir, force=True, overwrite=True)
mne.bem.make_watershed_bem(subject = str(subjid), subjects_dir=subjects_dir, overwrite=True)

```

I tried using a script to fix defects from [this GitHub post](https://github.com/mne-tools/mne-python/issues/8825), but I ran into issues there with degenerated faces not getting fixed by their code, which threw an error when it then tried to assert that there were no degenerated surfaces.

Any help would be appreciated!