Using Workbench Command

MEASURE DISTORTION BETWEEN SURFACES
   wb_command -surface-distortion
      <surface-reference> - the reference surface
      <surface-distorted> - the distorted surface
      <metric-out> - output - the output distortion metric

      [-smooth] - smooth the area data
         <sigma> - the size of the smoothing kernel in mm, as sigma by default

         [-fwhm] - kernel size is FWHM, not sigma

      [-caret5-method] - use the surface distortion method from caret5

      [-edge-method] - calculate distortion of edge lengths rather than areas

      [-local-affine-method] - calculate distortion by the local affines
         between triangles

         [-log2] - apply base-2 log transform

      This command, when not using -caret5-method, -edge-method, or
      -local-affine-method, is equivalent to using -surface-vertex-areas on
      each surface, smoothing both output metrics with the GEO_GAUSS_EQUAL
      method on the surface they came from if -smooth is specified, and then
      using the formula 'ln(distorted/reference)/ln(2)' on the smoothed
      results.

      When using -caret5-method, it uses the surface distortion method from
      caret5, which takes the base 2 log of the ratio of tile areas, then
      averages those results at each vertex, and then smooths the result on the
      reference surface.

      When using -edge-method, the -smooth option is ignored, and the output at
      each vertex is the average of 'abs(ln(refEdge/distortEdge)/ln(2))' over
      all edges connected to the vertex.

      When using -local-affine-method, the -smooth option is ignored.  The
      output is two columns, the first is the area distortion ratio, and the
      second is anisotropic strain.  These are calculated by an affine
      transform between matching triangles, and then averaged across the
      triangles of a vertex.