OpenRoads Designer CE 2021 Complex shape/line string to Linear Geometry.

I have have a file with many 2d complex shapes and line strings that I would like to convert to Linear Geometry elements. GDOT requires that my file be a 3D design file. Is there any easy way to do this? I tried using "Set Feature Definition" but it only yielded 3D Linear Elements. How do I get them under Linear Geometry in the OpenRoads Model as they require?