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Creating surface with polylines

12 REPLIES 12
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Message 1 of 13
estebanwesson
21075 Views, 12 Replies

Creating surface with polylines

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! 

12 REPLIES 12
Message 2 of 13
ccoles
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?

Windows 7 64-bit
Dell Precision T5610, Dual-Xeon 2.6Ghz, 16 Gig RAM
Civil 3D 2013
Message 3 of 13
tcorey
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
MicroCAD Training and Consulting, Inc.
Redding, CA
Autodesk Gold Reseller

New knowledge is the most valuable commodity on earth. -- Kurt Vonnegut
Message 4 of 13
sdhauban
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!

Message 5 of 13
Joe-Bouza
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)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 6 of 13
BrianHailey
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 J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 7 of 13
antoniovinci
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.

Message 8 of 13
wfberry
in reply to: antoniovinci

For the record.  I concur with Brian.

 

Bill

 

Message 9 of 13
troma
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.


Mark Green

Working on Civil 3D in Canada

Message 10 of 13
sdhauban
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.

 

Message 11 of 13

Changing the units isn't going to change the elements. You need to scale the objects in the drawing by a factor of 1/12 (0.083333333). You can do this either before or after you make the surface.

 

Cheers,

 

Peter Funk

Autodesk, Inc.



Peter Funk
Autodesk, Inc.

Message 12 of 13
tcorey
in reply to: peterfunkautodesk

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.

 

 



Tim Corey
MicroCAD Training and Consulting, Inc.
Redding, CA
Autodesk Gold Reseller

New knowledge is the most valuable commodity on earth. -- Kurt Vonnegut
Message 13 of 13
sdhauban
in reply to: tcorey

tcorey that worked!

 

Thank you guys so much!

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