R u trying to apply any computational techniques to ur waveguide structure for analysis ? I dont know how to get this data thru CST but if its a simple waveguide structure, then I think u can define them in Matlab directly..!!
@spacedust: i got it... we can do it using NASTRAN file (meant to export FEM mesh).. at the very beginning they are giving me the name of material used and then the mesh coordinate.. .