TTM File

I'm currently using Power InRoads V8i SS4.  In the past I've used the process in the link below to convert a DTM to a TTM for use in my Trimble survey grade GPS.  I've been unable to recreate this process with a new computer.  Any help with how to create convert a dtm to a ttm is appreciated.

I also have Open Roads Designer on my computer if that is my only option.

https://communities.bentley.com/products/road___site_design/w/road_and_site_design__wiki/9335/exporting-to-trimble-format

Thanks

Paul Backhaus