Chapter 10: Advanced Corridors, Intersections, and Roundabouts
Create corridors with noncenterline baselines. Although for simple corridors you may think of a baseline as a road centerline, other elements of a road design can be used as a baseline. In the case of a cul-de-sac, the EOP, the top of curb, or any other appropriate feature can be converted to an alignment and profile and used as a baseline.
Master It Open the Mastering Advanced Corridors.dwg file, which you can download from www.sybex.com/go/masteringcivil3d2012. Add the cul-de-sac alignment and profile to the corridor as a baseline. Create a region under this baseline that applies the Typical Intersection assembly.
Solution
1. Select the corridor, right-click, and choose Corridor Properties. Switch to the Parameters tab.
2. Click Add Baseline. Choose Cul de Sac EOP in the Pick A Horizontal Alignment dialog.
3. In the Profile column, click inside the <click here …> box. Choose Cul de Sac EOP FG in the Select A Profile dialog.
4. Right-click the new baseline. Choose Add Region. Select Intersection Typical in the Select An Assembly dialog box.
5. Click OK to leave the Corridor Properties dialog and build the corridor.
Add alignment and profile targets to a region for a cul-de-sac. Adding a baseline isn’t always enough. Some corridor models require the use of targets. In the case of a cul-de-sac, the lane elevations are often driven by the cul-de-sac centerline alignment and profile.
Master It Continue working in the Mastering Advanced Corridors.dwg file. Add the Second Road alignment and Second Road FG profile as targets to the cul-de-sac region. Adjust Assembly Application Frequency to 5′, and make sure the corridor samples are profile PVIs.
Solution
1. Select the corridor, right-click, and choose Corridor Properties. Switch to the Parameters tab.
2. Click the Target Mapping button in the appropriate region.
3. In the Target Mapping dialog, assign Second Road as the transition alignment and Second Road FG profile as the transition profile. Click OK to leave the Target Mapping dialog.
4. Click the Frequency button in the appropriate region. Change the Along Curves value to 5′ and the At Profile High/Low Point value to Yes. Click OK to exit the Frequency To Apply To Assemblies dialog.
5. Click OK to leave the Corridor Properties dialog and build the corridor.
Use the Interactive Boundary tool to add a boundary to the corridor surface. Every good surface needs a boundary to prevent bad triangulation. Bad triangulation creates inaccurate and unsightly contours. Civil 3D provides several tools for creating corridor surface boundaries, including an Interactive Boundary tool.
Master It Continue working in the Mastering Advanced Corridors.dwg file. Create an interactive corridor surface boundary for the entire corridor model.
Solution
1. Select the corridor, right-click, and choose Corridor Properties. Switch to the Boundaries tab.
2. Select the corridor surface, right-click, and choose Add Interactively.
3. Follow the command-line prompts to add a feature line–based boundary all the way around the entire corridor.
4. Type C to close the boundary, and then press ↵ to end the command.
5. Click OK to leave the Corridor Properties dialog and build the corridor.
An example of the finished exercise can be found in Mastering Advanced Corridors Finished.dwg at the book’s web page.