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: smooth.m
    path of file: ./repos/mtex/geometry/@vector3d
    
    the code of the file until where you have to start completion: function [h,ax] = smooth(v,varargin)
% low level function for plotting functions on the sphere
%
% Syntax
%   smooth(v,values)

    
function [h,ax] = smooth(v,varargin)
% low level function for plotting functions on the sphere
%
% Syntax
%   smooth(v,values)
%
% Input
%
% Output
%
% Options
%
% See also
%

h = [];

% initialize spherical plot
opt = delete_option(varargin,{'lineStyle','lineColor','lineWidth','color'},1);
sP = newSphericalPlot(v,opt{:},'doNotDraw');

for j = 1:numel(sP)
  
  % ---------------- extract colors --------------------------

  % color given by the first argument?
  if ~isempty(varargin) && ~isempty(varargin{1}) ...
      && (islogical(varargin{1}) || isnumeric(varargin{1})) 

    cdata = double(varargin{1});
    S2G = v;
    
  else % no color given -> do kernel density estimation

    sR = sP(j).sphericalRegion;
    if isfield(v.opt,'region'), sR = [sR,v.opt.region]; end