AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

Active Member
Posts: 10
Registered: ‎03-03-2010
Message 1 of 5 (776 Views)

Corridor back of curb

776 Views, 4 Replies
02-12-2013 10:40 AM

I am new to corridors and am having some trouble with this.  I have an assembly that has a paved roadway, 2' curb and gutter and a sidewalk.  Along the road the curb varies to allow for on street parking.  I have the front and back of sidewalk attached to an alignment, so it is exactly where it needs to be.  I have an alignment that my EOP follows as well, and that seems to be ok. The problem is the back fo curb in the corridor.  Instead of being 2' offset from the EOP, it is shifted 2' perpendicular to the baseline. Please take a look at the attached picture.


I think I can get it done by making each parking "bump out" it's own region using the EOP alignment, but that will take a lot more time and make my file a whole lot bigger. Being a corridor rookie, I am hoping I am just missing something.


I'm using Civil 3D 2013.


Thanks in advance.



Distinguished Mentor
Posts: 823
Registered: ‎11-15-2005
Message 2 of 5 (755 Views)

Re: Corridor back of curb

02-12-2013 11:42 AM in reply to: bfnaught

Yeah, that's how corridors work: everything is always perpendicular to the baseline. There are several things you can do, other than live with it:


1. Use an offset assembly. (See the "Help" files)

2. Dump the bump-out EOP alignment and instead use feature lines to model the bump-outs and add them to your surface. (It works, kind of, but can be cumbersome if you make changes to the corridor proper.)

3. Don't worry much about it and let it ride as you have it now. It will get the flowline and top of curb elevations correct, just not quite where you want them horizontally. There are much worst pitfalls in Civil 3D than that.

Active Member
Posts: 6
Registered: ‎03-05-2012
Message 3 of 5 (738 Views)

Re: Corridor back of curb

02-12-2013 12:32 PM in reply to: castled071049

When using feature lines for the bump out, they should be located where you want your lip of the C&G.  The assembly attaches at the lip line not the flowline.  That should give you the right horizontal location for the back of curb and flowline.



*Expert Elite*
Posts: 2,767
Registered: ‎12-18-2002
Message 4 of 5 (687 Views)

Re: Corridor back of curb

02-12-2013 09:24 PM in reply to: bfnaught

Another option: You could create two different baselines in the same corridor.


First would be a baseline using Centerline alignment and profile. Attach to your region an assembly that has a lane subassy. Set it's width target to the EOP alignment.


That same EOP alignment would be the second baseline (you'll need a profile also), to which you would attach an assembly that has only cgsw and only on one side.


Look on the parameters tab of corridor properties and you'll see where you can Add Baseline. Be sure to add a region to the second baseline because it's not added automatically when you add the new baseline.



Tim Corey, Owner
Delta Engineering Systems
Redding, CA
Autodesk Authorized Value-Added Reseller
Active Member
Posts: 10
Registered: ‎03-03-2010
Message 5 of 5 (640 Views)

Re: Corridor back of curb

02-20-2013 01:41 PM in reply to: bfnaught

Thanks for the suggestiong.  I looked into offset assemblies and have not been able to get them to work right.  I tried having a separate assembly running down an alignment at the EOP for the curb, and that worked better for the curb, but I couldn't get the sidewalk to properly follow the feature lines. I would just not worry about it, but it looks all jacked up in plan view.  I have moved onto something else right now, but will be getting back onto this soon and will look into having separate alignmets for the centerline of road and the curbs, with maybe the centerline assembly having a sidewalk offset.


Thanks again,


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