To set the default corridor settings for roundabouts, click the Home tab
Create Design panelJunctions drop-downConfigure Roundabout Tools.
Click Corridor in the left-hand pane.
The tick boxes control how much of the 3D model Autodesk Civil 3D creates and updates by default.
Select Create Alignments to create horizontal alignments in your CAD system.
Select Update Alignments if you want to update the alignments automatically when the geometry changes. This option is only available if Autodesk Civil 3D created the original alignments, i.e. if Create Alignments is selected
Select Create Profiles to create vertical profiles along the horizontal alignments.
Select Update Profiles if you want to update the profiles automatically when the geometry changes. This option is only available if Autodesk Civil 3D created the original profiles, i.e. if Create Profiles is selected
Select Create Corridor to create a 3D corridor model using default assemblies.
Select Update Corridor if you want to update the corridor automatically when the geometry changes. This option is only available if Autodesk Civil 3D created the original corridor, i.e. if Create Corridor is selected
By default, the corridor is built using simple assemblies consisting of just a road surface with no kerbs. This is the case when Use Simple Road Assembly is selected. These assemblies are based upon the Civil 3D Primary Road Through Junction assembly with right and left subassemblies renamed to offside and nearside in accordance with your driving convention.
Clear Use Simple Road Assembly to use more complex assemblies for the entry and exit roads. These assemblies are based on the Civil 3D Primary Road Part Section - Daylight Right (or Left) again with right and left renamed to offside and nearside in accordance with your driving convention.
Select Use Kerb Baselines to insert the assemblies on the nearside kerb alignment. If cleared, assemblies are inserted on the crown lines and targeted to the nearside kerb and centreline alignments.
Require Existing Surfaces