In this paper, we propose a method for constructing families of spacelike
surfaces in Minkowski 3-space 𝔼31
that share Bertrand curves as asymptotic
curves. By using marching-scale functions, we derive the necessary conditions,
provide flexible formulations, and establish a framework for constructing mutual
spacelike Bertrand curves. Examples show how different functions generate
surfaces interpolating the common asymptotic curves, offering new insights for
geometric modeling and ruled surface theory.