Our Terrain Builder module will allow you to construct digital contours (or topo) from spot shots. However, importing cross section data into the HEC-RAS module does not.
Also, if all you have is cross section data as XYZ, then the digital topo will be quite basic.
Let me know if I can help further.
Sincerely,
Chris E. Maeder, M.S., P.E.
Senior Technical Engineer
chris.maeder@bossintl.com