You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cat_surf_createCS2.m
    path of file: ./repos/ExploreASL/External/SPMmodified/toolbox/cat12
    
    the code of the file until where you have to start completion: function [Yth,S,Psurf,EC,defect_size,res] = cat_surf_createCS2(V,V0,Ym,Ya,YMF,Ytemplate,opt)
% ______________________________________________________________________
% Surface creation and thickness estimation.
%
% [Yth1,S,Psurf,EC]=cat_surf_createCS(V,V0,Ym,Ya,YMF,Ytemplate,opt)
%
% Yth1   .. thickness map
% S      .. structure with surfaces, like the left hemisphere, that contains
%           vertices, faces, GM thickness (th1)
% Psurf  .. name of surface files
% EC     .. Euler characteristics
% defect_size .. size of topology defects
% res    .. intermediate and final surface creation information
% V      .. spm_vol-structure of internally interpolated image
% V0     .. spm_vol-structure of original image
% Ym     .. the (local) intensity, noise, and bias corrected T1 image
% Ya     .. the atlas map with the ROIs for left and right hemispheres
%           (this is generated with cat_vol_partvol)
% YMF    .. a logical map with the area that has to be filled
%           (this is generated with cat_vol_partvol)
% Ytemplate ..
    
function (in development, RD2019)
  def.sharpenCB           = 1;                                % sharpening function for the cerebellum (in development, RD2017-2019)
  def.thick_measure       = 1;                                % 0-PBT; 1-Tfs (Freesurfer method using mean(TnearIS,TnearOS))
  def.thick_limit         = 5;                                % 5mm upper limit for thickness (same limit as used in Freesurfer)
  def.collcorr            = 5;                                % correction of surface collisions: 0 - none; 1 - CG (extract_pial_white); 2 - CAT_SI, 3 - PBT, 4 - PBT+, 5 - PBT+ & CAT_SI 
  def.surf_measures       = 1;                                % 0 - none, 1 - only thickness, 2 - expert maps (myelin,defects), 3 - developer (WMT,CSFT, ...),
                                                              % 4 - debug output, 5 - debug extended (more substeps and mex output)
  %def.new_release         = 0;                                % developer flag to test new functionality for new release (currently not used)
  %def.WMT                 = 0;                                % pbt-based WM/CSF width/depth/thickness estimation 
  def.fsavgDir            = fullfile(spm('dir'),'toolbox','cat12','templates_surfaces'); 
  def.add_parahipp        = cat_get_defaults('extopts.add_parahipp');
  def.scale_cortex        = cat_get_defaults('extopts.scale_cortex');
  def.close_parahipp      = cat_get_defaults('extopts.close_parahipp');
  def.reduce_mesh         = 1;  % 0 - surface creation on PBT resolution, no mesh-reduction (very slow) 
                                % 1 - optimal resolution depend