AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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estebanwesson
Posts: 1
Registered: ‎10-30-2012
Message 1 of 13 (5,377 Views)
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Creating surface with polylines

5377 Views, 12 Replies
10-30-2012 10:47 AM

Hi everyone, 

They send me a file that has polylines as contours and when I try to do the surface adding contours an error appears saying that the breaklines couldn't be added because they crossed a breakline, I don't understand why. Any help would be greatly appreciated! 

Except that I think he said the objects are incorrect in their elevations only. Scaling will mess up the x and y.

 

If that's the case, here's a lisp routine that will change only the elevations of your objects. This will select all LWpolylines not on frozen layers, so freeze all layers except the layers that contain your contours/polylines.

 

Use Appload to load the routine. It will run automatically upon load.

 

 

Valued Mentor
ccoles
Posts: 327
Registered: ‎06-26-2007
Message 2 of 13 (5,362 Views)

Re: Creating surface with polylines

10-30-2012 11:22 AM in reply to: estebanwesson

I'm confused. Are you adding them as contours or breaklines? You should not be getting this error if your adding them as contours. Is this a blank surface, or does it contain other data elements, like feature lines or breaklines?

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tcorey
Posts: 2,616
Registered: ‎12-18-2002
Message 3 of 13 (5,358 Views)

Re: Creating surface with polylines

10-30-2012 11:33 AM in reply to: estebanwesson

If any two polylines intersect you will get this error. You can modify the build options of the surface to allow crossing breaklines and then all contour polylines will be added.

 

Prospector tab of Toolspace, expand Surfaces, right click your surface, select Surface Properties. Go to the Definition tab, expand Build. Set Allow crossing breaklines to Yes.

Tim Corey, Owner
Delta Engineering Systems
Redding, CA
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sdhauban
Posts: 3
Registered: ‎11-17-2012
Message 4 of 13 (5,272 Views)

Re: Creating surface with polylines

11-17-2012 11:08 PM in reply to: estebanwesson

Hi,

 

I am new with Civil3D and I am having issues with creating a surface from polylines as well. I was given a topographic map with contours and the map scale was 1"=30'. So I converted the lines from the map to polylines, scaled them up and set their elevations to that for the contour lines. I also trimmed my map to include only the area I am interested in. Then I followed the instructions to create a surface from contour lines. I have a surface but the elevation range for the surface is (5700-6276ft) while the original contour lines are (475-525ft). Any idea why this might be happening and how I can deal with this?

 

I am using Civil 3D 2013. My end goal is to export the data to HEC-RAS to do hydraulic modeling.

 

Thanks!

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Joe-Bouza
Posts: 4,985
Registered: ‎12-15-2008
Message 5 of 13 (5,255 Views)

Re: Creating surface with polylines

11-18-2012 03:14 PM in reply to: sdhauban

Scaling up the drawing I suspect? Was this a digitized paper map at 30 scale? It would be unusual for a cad drawing of a topo be drawn at something other than one to one world

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People) Civil 3D 2012 & 2013
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BrianHailey
Posts: 2,815
Registered: ‎04-27-2005
Message 6 of 13 (5,246 Views)

Re: Creating surface with polylines

11-18-2012 08:00 PM in reply to: ccoles

ccoles wrote:

I'm confused. Are you adding them as contours or breaklines? You should not be getting this error if your adding them as contours. Is this a blank surface, or does it contain other data elements, like feature lines or breaklines?


The ONLY difference between adding objects as breaklines vs. adding them as contours is when you add them as contours, you must weed and supliment them and you get the option to minimize flat areas. Other than that, they are exactly the same and you will get the message about breaklines crossing (assuming the contours cross each other).

Brian Hailey
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antoniovinci
Posts: 1,681
Registered: ‎06-03-2011
Message 7 of 13 (5,235 Views)

Re: Creating surface with polylines

11-19-2012 02:23 AM in reply to: BrianHailey
BrianHailey wrote:
Other than that, they are exactly the same


Sorry B., but I think you should not let these words read to the young readers of this forum.


Even if contours and breaklines behave identically in Autocad, they are DEFINETELY different from the conceptual point of view: contours describe the raw surface of a terrain, while breaklines are put where that surface must stop because of a river, a road, and so on...


You cannot mix these two notions, that's my humble opinion.

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wfberry
Posts: 1,870
Registered: ‎09-05-2006
Message 8 of 13 (5,214 Views)

Re: Creating surface with polylines

11-19-2012 06:31 AM in reply to: antoniovinci

For the record.  I concur with Brian.

 

Bill

 

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troma
Posts: 2,520
Registered: ‎05-21-2008
Message 9 of 13 (5,207 Views)

Re: Creating surface with polylines

11-19-2012 07:46 AM in reply to: sdhauban

@ sdhauban

It occurs to me that your elevations are off by a factor of 12.  I suggest looking into the units settings in your drawing; something is in inches that needs to be feet, or vice versa.


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sdhauban
Posts: 3
Registered: ‎11-17-2012
Message 10 of 13 (5,196 Views)

Re: Creating surface with polylines

11-19-2012 09:25 AM in reply to: estebanwesson

Thank you all! antoniovinci thank you for the clarification.

 

troma, it might be some unit error. I went back and checked, the units in my Drawing Setting is set to Feets. In the Drawing Units window I had Inches as my units. I changed that to feets and updated my surface but it still gives me the same values. I'll keep looking into the units and see if I can figure this out.

 

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