Can Cross Sections in SS3 work with pre-existing .alg file?
Yes, but you will need to import the ALG into OpenRoads by using the Import Geometry tool.
Please refer to the following wiki for detailed information:
http://communities.bentley.com/products/road___site_design/w/road_and_site_design__wiki/17897.video-import-native-geometry-into-openroads
Answer Verified By: cbfurman