[Freesurfer] Generate mask from surface in diffusion space

Dear freesurfers

I'm using bbregister and mri_surf2surf to transform intermediate cortical surfaces and mid surfaces normals to diffusion space. Next I'm trying to generate volumes from these surfaces (in the same diffusion space), however the generated volumes are much thicker then the generated surfaces. for example to generate surface normals I used the following: mri_surf2surf --s subjectid --hemi lh --sval-nxyz white_surface_in_diffusion --tval lhwhitediffusion_n.mgh mri_surf2vol --surfval lhwhitediffusion_n.mgh --hemi lh --surf white --reg mri/register.dat --outvol lh_white_n.img --template lowb.img Any idea what am I doing wrong?

Thanks!

Shani