Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_plot_vol”.

  FT_PLOT_VOL visualizes the boundaries in the volume conduction model of the head as
  specified in the headmodel structure
 
  Use as
    hs = ft_plot_vol(headmodel, varargin)
 
  Optional arguments should come in key-value pairs and can include
    'facecolor'    = [r g b] values or string, for example 'brain', 'cortex', 'skin', 'black', 'red', 'r', or an Nx3 or Nx1 array where N is the number of faces
    'vertexcolor'  = [r g b] values or string, for example 'brain', 'cortex', 'skin', 'black', 'red', 'r', or an Nx3 or Nx1 array where N is the number of vertices
    'edgecolor'    = [r g b] values or string, for example 'brain', 'cortex', 'skin', 'black', 'red', 'r'
    'faceindex'    = true or false
    'vertexindex'  = true or false
    'facealpha'    = transparency, between 0 and 1 (default = 1)
    'edgealpha'    = transparency, between 0 and 1 (default = 1)
    'surfaceonly'  = true or false, plot only the outer surface of a hexahedral or tetrahedral mesh (default = false)
    'unit'         = string, convert to the specified geometrical units (default = [])
    'grad'         = gradiometer array, used in combination with local spheres model
 
  Example
    headmodel   = [];
    headmodel.r = [86 88 92 100];
    headmodel.o = [0 0 40];
    figure, ft_plot_vol(headmodel)
 
  See also FT_PREPARE_HEADMODEL, FT_PLOT_MESH, FT_PLOT_SENS