These tutorials will get you started working with junctions and roundabouts.
A junction object is created from two intersecting alignments that have design profiles. During the junction creation process, alignments and profiles are automatically generated for the offset and radius kerb geometry. The horizontal and vertical geometry of the offsets and radius kerbs is dynamically linked to the junction object. When changes are made to the centerline alignments or profiles, the offset and radius kerb geometry is automatically updated.
A roundabout is created from two or more alignments that may or may not intersect. During the roundabout creation process, alignments are automatically generated for the offset and corner radius geometry. The process also creates AutoCAD linework and blocks that represent traffic islands, pavement markings, and signs. The alignments and AutoCAD objects are dynamically linked to the parent alignments.
The primary difference between a junction and a roundabout is that a junction is a AutoCAD Civil 3D object that is dynamic in both 2D and 3D. Profiles, corridors, and assemblies can be created automatically during the junction creation process. A roundabout is a collection of 2D alignments that, while dynamic to one another in 2D, have no relationship in 3D. Profiles, corridors, and assemblies must be created independent from the roundabout, and they are not dynamically linked to each other or the roundabout.
All drawings used in these tutorials are available in the tutorials drawings folder. If you want to save your work from these tutorials, save the drawings to the My Tutorial Data folder so that you do not overwrite the original drawings.