AEC Modify - Trim

You can use the AEC Modify Trim to edges of Civil 3D objects (or any other objects). Just choose it from the right click menu, choose the object you want to trim, then hit enter to be able to select an edge in the drawing, then select the edge in the drawing (a red line will appear indicating the edge that will be selected), then choose the side you want trimmed.

This is helpful for trimming against Civil 3D objects that you can't trim to using the normal trim command. For instance if you have a line in profile view and you want it trimmed to a profile you can do it with this command. The only thing lacking in my opinion is the ability to select a profile vertical curve as an edge.