Hi,
I have a couple of questions about the two different ways to generate BEM surfaces available in FreeSurfer. I have done a comparison of the techniques available in mri_watershed -surf mri_make_bem_surfaces (Version 4.3.0) with another algorithm (which I know the algorithm) I have received a request from reviewers to briefly describe how each of the first two techniques develops the surfaces. I have read all of the Ségonne 2004 paper several times and while I believe I can explain how the "brain"/"inner skull" surface is generated. I cannot figure out how the other two surfaces are generated: "outer skull" and "outer skin" surfaces.
Additionally, I cannot find any information about mri_make_bem_surfaces either on the wiki or in the email archives (I realize this software may be kept in as a courtesy to the MEG users: my tests suggest this is very useful). Is there anyone who can provide even a brief description of how this tool generates the surfaces?
Thank You, Dan