Using Workbench Command

COPY REGISTRATION DEFORMATIONS TO DIFFERENT SPHERE
   wb_command -surface-sphere-project-unproject
      <sphere-in> - a sphere with the desired output mesh
      <sphere-project-to> - a sphere that aligns with sphere-in
      <sphere-unproject-from> - <sphere-project-to> deformed to the desired
         output space
      <sphere-out> - output - the output sphere

      Background: A surface registration starts with an input sphere, and moves
      its vertices around on the sphere until it matches the template data.
      This means that the registration deformation is actually represented as
      the difference between two separate files - the starting sphere, and the
      registered sphere.  Since the starting sphere of the registration may not
      have vertex correspondence to any other sphere (often, it is a native
      sphere), it can be inconvenient to manipulate or compare these
      deformations across subjects, etc.

      The purpose of this command is to be able to apply these deformations
      onto a new sphere of the user's choice, to make it easier to compare or
      manipulate them.  Common uses are to concatenate two successive separate
      registrations (e.g. Human to Chimpanzee, and then Chimpanzee to Macaque)
      or inversion (for dedrifting or symmetric registration schemes).

      <sphere-in> must already be considered to be in alignment with one of the
      two ends of the registration (if your registration is Human to
      Chimpanzee, <sphere-in> must be in register with either Human or
      Chimpanzee).  The 'project-to' sphere must be the side of the
      registration that is aligned with <sphere-in> (if your registration is
      Human to Chimpanzee, and <sphere-in> is aligned with Human, then
      'project-to' should be the original Human sphere).  The 'unproject-from'
      sphere must be the remaining sphere of the registration (original vs
      deformed/registered).  The output is as if you had run the same
      registration with <sphere-in> as the starting sphere, in the direction of
      deforming the 'project-to' sphere to create the 'unproject-from' sphere.

      Note that this command cannot check for you what spheres are aligned with
      other spheres, and using the wrong spheres or in the incorrect order will
      not necessarily cause an error message.  In some cases, it may be useful
      to use a new, arbitrary sphere as the input, which can be created with
      the -surface-create-sphere command.

      Example 1: You have a Human to Chimpanzee registration, and a Chimpanzee
      to Macaque registration, and want to combine them.  If you use the Human
      sphere registered to Chimpanzee as sphere-in, the Chimpanzee standard
      sphere as project-to, and the Chimpanzee sphere registered to Macaque as
      unproject-from, the output will be the Human sphere in register with the
      Macaque.

      Example 2: You have a Human to Chimpanzee registration, but what you
      really want is the inverse, that is, the sphere as if you had run the
      registration from Chimpanzee to Human.  If you use the Chimpanzee
      standard sphere as sphere-in, the Human sphere registered to Chimpanzee
      as project-to, and the standard Human sphere as unproject-from, the
      output will be the Chimpanzee sphere in register with the Human.

      Technical details: Each vertex of <sphere-in> is projected to a triangle
      of <sphere-project-to>, and its new position is determined by the
      position of the corresponding triangle in <sphere-unproject-from>.  The
      output is a sphere with the topology of <sphere-in>, but coordinates
      shifted by the deformation from <sphere-project-to> to
      <sphere-unproject-from>.  <sphere-project-to> and <sphere-unproject-from>
      must have the same topology as each other, but <sphere-in> may have any
      topology.