[Freesurfer] How can I increase radius of a binary disk?

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Dear Dr. Douglas N. Greve,

Thanks to you, I could have a binary disk approximately 3mm in radius by the codes you told me (https://secure-web.cisco.com/1z0F3-vP1KDJI6B_AsTyKAaKNmMd0vO7tGkwv_YiAe4mgtF...):

mri_volsynth --dim-surf fsaverage/surf/lh.white --pdf delta --delta-crsf ${vertexno} 0 0 0 --0 delta.mgh mris_fwhm --i delta.mgh --o delta.sm3.mgh --s fsaverage --hemi lh mri_binarize --i delta.sm3.mgh --min 0.5 --o delta.sm3.bin.mgh

I have sincerely appreciated your help.

Now I'm wondering how to modulate the radius. I guess I can do it by adding --fwhm option to mris_fwhm command, for example: mris_fwhm --i delta.mgh --o delta.sm3.mgh --s fsaverage --hemi lh --fwhm 5 At the end, I will get a binary disk with 5mm in radius. Am I right? And does this mean that --fwhm 3 is default for mris_fwhm? How could you define 3mm?

Kind Regards, Andy (Junghyun) Kim