I was hoping to be able to extract a "pattern line" equivalent from my model in order to use line strings to generate traditional cross sections. In SS2 there was a way to generate Transverse Features, but I'm not seeing anything similar in SS3.
It looks to me like my best best will be to generate pattern lines in the traditional manner, then create a graphic at any bends in the pattern lines to be used as a secondary alignment in the model to force the model to bend as prescribed by the pattern lines. Then the pattern lines should align with the model for creating cross sections from linestrings.