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

  FT_HEADMODELPLOT makes a 3D visualisation of the volume conductor model
  and optionally of the gradiometer positions and headshape. It can
  be used for example to check CTF multiple-sphere head models.
  Use as
    ft_headmodelplot(cfg, data)
  You should specify the volume conductor model with
    cfg.hdmfile       = string, file containing the volume conduction model
  or alternatively
    cfg.vol           = structure with volume conduction model
  If the sensor information is obtained by FT_FETCH_SENS.
  The positions of the sources can be specified as a regular 3-D
  grid that is aligned with the axes of the head coordinate system
    cfg.grid.xgrid      = vector (e.g. -20:1:20) or 'auto' (default = 'auto')
    cfg.grid.ygrid      = vector (e.g. -20:1:20) or 'auto' (default = 'auto')
    cfg.grid.zgrid      = vector (e.g.   0:1:20) or 'auto' (default = 'auto')
    cfg.grid.resolution = number (e.g. 1 cm) for automatic grid generation
  Alternatively the position of a few sources at locations of interest can
  be specified, for example obtained from an anatomical or functional MRI
    cfg.grid.pos        = Nx3 matrix with position of each source
    cfg.grid.dim        = [Nx Ny Nz] vector with dimensions in case of 3-D grid (optional)
    cfg.grid.inside     = vector with indices of the sources inside the brain (optional)
    cfg.grid.outside    = vector with indices of the sources outside the brain (optional)
  You can also use the FT_PREPARE_LEADFIELD or FT_SOURCEANALYSIS functions
  to create a grid with dipole positions.
  Other options are          = cell-array, see FT_CHANNELSELECTION
    cfg.spheremesh       = number of vertices for spheres, either 42, 162 or 642
    cfg.plotheadsurface  = 'yes' or 'no', is constructed from head model
    cfg.plotbnd          = 'yes' or 'no'
    cfg.plotspheres      = 'yes' or 'no'
    cfg.plotspherecenter = 'yes' or 'no'
    cfg.plotgrid         = 'yes' or 'no'
    cfg.plotinside       = 'yes' or 'no'
    cfg.plotoutside      = 'yes' or 'no'
    cfg.plotsensors      = 'yes' or 'no' plot electrodes or gradiometers
    cfg.plotcoil         = 'yes' or 'no' plot all gradiometer coils
    cfg.plotlines        = 'yes' or 'no' plot lines from sensor to head surface
    cfg.surftype         = 'edges'or 'faces'
    cfg.headshape        = a filename containing headshape, a structure containing a
                           single triangulated boundary, or a Nx3 matrix with surface
  To facilitate data-handling and distributed computing with the peer-to-peer
  module, this function has the following option:
    cfg.inputfile   =  ...
  If you specify this option the input data will be read from a *.mat
  file on disk. This mat files should contain only a single variable named 'data',
  corresponding to the input structure.