code: def _bend_cos_low(a, b, deriv):
      
      a = Vector3(6, deriv, a, (0, 1, 2))
      b = Vector3(6, deriv, b, (3, 4, 5))
      a /= a.norm()
      b /= b.norm()
      return dot(a, b).results()
docs: Similar to bend_cos, but with relative vectors