Hello Alain,

Sorry for the delay. What you can do is convert each of the surfaces to .1D format with ConvertSurface, then use 3dMean to average the coords. Here is an example that does this for just two surfaces, the pial and smoothwm surfaces. You can do this for any set of surfaces at hand, as long as they are isotopic of course. This means you can do this on any set of standard meshes with the same density. Note that it is possible to get a surface with self intersections this way, but in most cases you won't and if you do they're likely small and may be irrelevant for your needs.

Sample commands:


ConvertSurface -i std.60.lh.pial.gii -o_1D test.pial test.pial
ConvertSurface -i std.60.lh.smoothwm.gii -o_1D test.smooth test.smooth

3dMean -prefix test.ave test.smooth.1D.coord test.pial.1D.coord

suma -i test.ave.1D test.pial.1D.topo



cheers,
z