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

  FT_CONVERT_UNITS changes the geometrical dimension to the specified SI unit.
  The units of the input object is determined from the structure field
  object.unit, or is estimated based on the spatial extend of the structure,
  e.g. a volume conduction model of the head should be approximately 20 cm large.
 
  Use as
    [object] = ft_convert_units(object, target)
 
  The following geometrical objects are supported as inputs
    electrode or gradiometer array, see FT_DATATYPE_SENS
    volume conductor, see FT_DATATYPE_HEADMODEL
    anatomical mri, see FT_DATATYPE_VOLUME
    segmented mri, see FT_DATATYPE_SEGMENTATION
    dipole grid definition, see FT_DATATYPE_SOURCE
 
  Possible target units are 'm', 'dm', 'cm ' or 'mm'. If no target units
  are specified, this function will only determine the native geometrical
  units of the object.
 
  See also FT_DETERMINE_UNITS, FT_CONVERT_COORDSYS, FT_DETERMINE_COODSYS