AutoCAD Civil 3D Wishes

AutoCAD Civil 3D Wishes

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Registered: ‎10-02-2007
Post 1 of 5

Assembly Offsets Vertical Control.

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07-11-2011 12:38 PM

I have an straight urban roadway with pocketed parking and bulbing.  If I do not use the assembly offset, my curbs, gutters, and sidewalk get skinnier where they become un-parallel with the centerline alignment.  As I am designing my roadway, I want to set up my alignment, Initial proposed centerline profile, cut my cross sections, then adjust my proposed profile up and down until I can make sure my new curb is not blocking drainage from the fronting properties.


The proper way to do this is to use assembly offsets to eliminate the errors caused by corridor lines not being perpendicular with the curb and gutter, but when I use Assembly offsets, I have to specify a profile for the offset.  What I would like the offset to do is to follow the grades of the edge of AC at the lip of gutter, based on the centerline profile, the value of the offset, and the cross slope between the centerline and the lip of gutter.


Is there a way the vertical component of the assembly offset can follow a profile based on the edge of pavement?  It appears at this point, I need to create profile from corridor, then target that profile for the assembly offset vertical.  The problem with this is that the profile from the corridor is static and does not automatically update when the other profile is changed.


Any thoughts on how to overcome this dilemma?





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Registered: ‎07-06-2011
Post 2 of 5

Re: Assembly Offsets Vertical Control.

07-13-2011 05:55 AM in reply to: lgreen
There is a "hack" way of doing what you want. YMMV Create another surface of your corridor with only the ETW feature line. Profile your offset alignment against this surface. Use as your offset's profile. Your offset alignment now follows the main corridor ETW. Of course you have to disable rebuild automatic since you have created an infinite loop and you will need to rebuild at least twice. But once you're relatively happy, just substitute with a design profile.
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Registered: ‎10-02-2007
Post 3 of 5

Re: Assembly Offsets Vertical Control.

11-02-2012 10:16 AM in reply to: BHFH

This is basically the way I had to do it, but I would like to see Autodesk consider making this more automated.  If I could use an alignment from one source and a profile from a different alignment, this would greatly automate things and be more accurate.  Or, if I could use a superimposed profile to attach to...this would also work.


I hope they consider this.


Thanks for any help you can give.



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Post 4 of 5

Re: Assembly Offsets Vertical Control.

11-06-2012 11:17 AM in reply to: lgreen

Maybe I'm misunderstanding, but can't you specify an alignment target without specifying a profile target?  I did recently. Is that what you need?

I was working with a very simple corridor, and it sounds like you have something more complex going on.

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Registered: ‎01-07-2011
Post 5 of 5

Re: Assembly Offsets Vertical Control.

11-16-2012 06:49 AM in reply to: troma

Civil 3D doesn't orient the subassembly links properly outside of a transitioning alignment. They should be perpendicular to the transitioning alignment, not the centerline alignment.


The required workaround he mentions, using an assembly offset,  has to be done every time,  just to get the correct outer subassembly orientation in a transitioning alignment scenario.


An assembly offset requires an Alignment and Profile, unless you use the MarkPoint setup that Peter Funk has previously described, then you don't need a Profile.


Note: Superelevation axis of rotation does not support assembly offsets altogether, so neither works here.


This is all more overhead to simply effect correct subassembly orientation that should be occurring outside of a transitioning alignment in the first place. If you don't go through all of this, your design outside of the transitioning alignment will be wrong, and you would not be able to use the Corridor to generate correct construction staking data.


If you don't take these steps, your sidewalk could be staked incorrectly and built with incorrect cross slopes for example, or for instance your outer channel/ditch would be staked incorrectly. Then you could be handed the bill from the contractor for replacement and repairs.


It's the elephant in the room. I think they just hope you don't mind working around the big fella.



Fred Ernst, PE
C3D 2015 SP2
Ernst Engineering
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