[Freesurfer] Cropping/slicing surfaces & read in matlab

I am able to load patch ok in tksurfer, however I get the following error message when trying to read the patch in Matlab. Attached you find the original surface (sub_), and its patch (inner-). Any help appreciated. Alternatively, you suggested to modify the ripflag=1 for the hemi to be left out, in this case for x<0, how would I do it in read_surf?

fname_patch='/usr/local/freesurfer/subjects/sub/surf/rh.inner-skull-surface'

fname_patch =

/usr/local/freesurfer/subjects/sub/surf/rh.inner-skull-surface

...

read_patch

Attempted to access poly(1); index out of bounds because numel(poly)=0.

Error in read_patch (line 41) numvert = poly(1); Thank you very much, Octavian