Hi AFNI group:

I was trying to map data from a surface domain to an AFNI volume domain by 3dSurf2Vol, with left hemi and right hemi separately.
But with using 3dcalc to combine the left and right hemi volume together, I realized that there were some overlaping voxels between left and right hemi. I'm not sure where goes wrong.
I have tried different parameters of -map_func, well, it turns out this parameters do have influnce on the results, but it never got perfect separated left and right hemi without overlapping.

Below are commands:

foreach hemi (lh rh)
3dSurf2Vol \
-spec "$spath"/group/Freesurfer/SUMA/subAvg_"$hemi"+tlrc.spec \
-surf_A smoothwm \
-surf_B pial \
-sv "$spath"/group/subAvg_SurfVol_at+tlrc.nii.gz \
-grid_parent "$spath"/sub01/map2sub2g/ts_normalized+tlrc.nii.gz \
-sdata_1D "$hemi"_"$infile"_"$test"_"$thresh".dset \
-map_func mode \
-f_steps 2 \
-f_index voxels \
-prefix "$hemi"_"$infile"_"$test"_"$thresh"_sb
end
## combine left and right hemi together
3dcalc \
-float -prefix "$infile"_"$test"_"$thresh".nii \
-a lh_"$infile"_"$test"_"$thresh"_sb+tlrc. \
-b rh_"$infile"_"$test"_"$thresh"_sb+tlrc. \
-expr '(a+b)'

Thanks !!!