Sorry, one more thing.
I am not so sure anymore that the scaling is the problem, because if I open my eeg.fif file in the coregistration gui and fit ICP, the median distances look fine:
Channel types:: eeg: 257
Aligning using fiducials
Start median distance: 7.48 mm
End median distance: 2.20 mm
Fitting fiducials finished in 0.22 seconds.
Channel types:: eeg: 257
Aligning using ICP
Start median distance: 2.20 mm
ICP 1 median distance: 2.11 mm
Fitting ICP - iteration 1
Channel types:: eeg: 257
ICP 2 median distance: 2.12 mm
Fitting ICP - iteration 2
Channel types:: eeg: 257
ICP 3 median distance: 2.15 mm
Fitting ICP - iteration 3
Channel types:: eeg: 257
ICP 4 median distance: 2.08 mm
Fitting ICP - iteration 4
Channel types:: eeg: 257
ICP 5 median distance: 2.05 mm
Fitting ICP - iteration 5
Channel types:: eeg: 257
ICP 6 median distance: 2.02 mm
Fitting ICP - iteration 6
Channel types:: eeg: 257
ICP 7 median distance: 1.98 mm
Fitting ICP - iteration 7
Channel types:: eeg: 257
End median distance: 1.98 mm
Fitting ICP finished in 2.34 seconds and 7 iterations.
Could this error message after cloing the gui play a role?
2023-04-20 17:19:49.910 (1253.899s) [ ] vtkRenderer.cxx:1172 WARN| vtkOpenGLRenderer (000002985F57A860): Resetting view-up since view plane normal is parallel