Thanks for reply. I am Chaitanya from Tata Motors Ltd. I am using COSIN 2018-1.
When I was trying to import .stl file of road geometry, I was getting message, "error loading triangulated road data". Then, I imported the parasolid file of that CAD road model in ADAMS and exported as '.shl' file from ADAMS. That '.shl' file then I tried to import in COSIN 2018-1. This time it got imported without any error. Now I exported '.rdf' from COSIN 2018-1 to use in ADAMS for Full vehicle simulations.