AutoCAD Map 3D General Discussion

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neilyj
Posts: 3,694
Registered: ‎08-01-2008
Message 1 of 8 (945 Views)
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Export Contour Layer for use in Civil 3D

945 Views, 7 Replies
06-20-2013 08:30 AM

I've brought in a raster elevation file and have created a contour layer and I now want to use the contours in Civil 3D. I have done this several months ago but can't remember how I did it but I seem to remember it took several steps

 

Can anyone remind me how to do this?

 

Thanks

neilyj
(No connection with Autodesk other than using the products in the real world)


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Alfred.NESWADBA
Posts: 8,893
Registered: ‎06-29-2007
Message 2 of 8 (941 Views)

Re: Export Contour Layer for use in Civil 3D

06-20-2013 08:59 AM in reply to: neilyj

Hi,

 

first step is to use _MAPIMPORT to import the polylines and the objectdata (especially the field ELEVATION).

Save this drawing, close it. Create a new drawing and use command _ADEDRAWINGS and assign the previous dwg now.

Start command _ADEQUERY and query the entities with the option "CHANGE PROPERTIES" (hope this is called so in the English version) and define the elevation of the polyline that is created has to be overridden from the object-data field ELEVATION.

 

HTH, - alfred -

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Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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Murph
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Registered: ‎11-13-2006
Message 3 of 8 (920 Views)

Re: Export Contour Layer for use in Civil 3D

06-20-2013 05:12 PM in reply to: neilyj

Once you created the SDF of the contours you can convert it to shp and use the Surface from GIS  tools in Civil3d. You may need to do a little contour smoothing on the lines.

Murph
Supportting the troops daily.
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neilyj
Posts: 3,694
Registered: ‎08-01-2008
Message 4 of 8 (908 Views)

Re: Export Contour Layer for use in Civil 3D

06-21-2013 12:37 AM in reply to: Murph

Thanks to both of you - worked like a charm.

I have a question though:

I used a raster level grid with a 50m spacing and using MAP and contour layers the contours at 1m spacing were pretty smooth and looked "good" but when I created a surface in CIVIL using the same raster data the contours were dreadful with 90 degree bends etc. Any idea why this should be the case?

This is why I wanted to use the MAP method - not bothered if the contours aren't a perfect reflection of the ground but they must look correct.

neilyj
(No connection with Autodesk other than using the products in the real world)


IDSP Premium 2015 (mainly Civil 3D 2015 UKIE & Infraworks with some limited 3ds Max Design)
Win 7 Pro x64, 240Gb SSD, 1Tb HDD
32Gb Ram Intel Xeon CPU E5-2650 v2 @ 2.6GHz (32 CPUs), ~2.6GHz
NVIDIA Quadro K4000, Dual 27" Monitor, Dell T5610
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Alfred.NESWADBA
Posts: 8,893
Registered: ‎06-29-2007
Message 5 of 8 (903 Views)

Re: Export Contour Layer for use in Civil 3D

06-21-2013 12:54 AM in reply to: neilyj

Hi,

 

>> [...] 90 degree bends [...] Any idea why this should be the case?

Because Civil imports first the points and as the pixels in the raster a rectangular you'll get contours with 90 degree.

And as long as you don't want to run methods like smooth surface (which creates surfaces different to the dem, but smoother or "more beautiful contours then") I guess there are not to many ways to avoid that.

 

As you tried both ways it would be interesting to have both contour-results shown concurrently to compare them and so to see if Map3D/FDO has the better algorithm or is more away from reality :smileywink:

 

- alfred -

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Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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neilyj
Posts: 3,694
Registered: ‎08-01-2008
Message 6 of 8 (899 Views)

Re: Export Contour Layer for use in Civil 3D

06-21-2013 01:29 AM in reply to: Alfred.NESWADBA

The Red contours are derived via MAP and the Grey via Civil 3D - both used the same source files.

 

The MAP version is certainly more pleasing to the eye...:smileyhappy: and for my purposes is a better one to use.

 

A full topo survey will need to be done eventually for detailed design work but this is ok for now

neilyj
(No connection with Autodesk other than using the products in the real world)


IDSP Premium 2015 (mainly Civil 3D 2015 UKIE & Infraworks with some limited 3ds Max Design)
Win 7 Pro x64, 240Gb SSD, 1Tb HDD
32Gb Ram Intel Xeon CPU E5-2650 v2 @ 2.6GHz (32 CPUs), ~2.6GHz
NVIDIA Quadro K4000, Dual 27" Monitor, Dell T5610
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Alfred.NESWADBA
Posts: 8,893
Registered: ‎06-29-2007
Message 7 of 8 (894 Views)

Re: Export Contour Layer for use in Civil 3D

06-21-2013 01:53 AM in reply to: neilyj

Hi,

 

>> The MAP version is certainly more pleasing to the eye

Yep, and only for the eye :smileywink:

Looking to that area and the marked contour:

2013-06-21 10-44-42.png

You'll recognize that this red contour crosses 3 Civil3D contours. As I assume that Civil3D really evaluates every single rasterpoint for creating the contour (and therefor generates 90°-corners sometimes) my feeling is that Map3D does contour-generalization with really big tolerance values.
So don't forget to put the info about data source (and generalization of contours) into the description area of the surface-properties. At least that is my way to save the info so everyone looking to this surfaces (now or years later) knows how to interpret it's quality.

 

Thx for the screenshot, I have not yet verified that in detail :smileywink:

 

- alfred -

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Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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*Expert Elite*
neilyj
Posts: 3,694
Registered: ‎08-01-2008
Message 8 of 8 (892 Views)

Re: Export Contour Layer for use in Civil 3D

06-21-2013 02:38 AM in reply to: Alfred.NESWADBA
Yes - the contour spacing is 1m so some potentially major anomalies between the derived surfaces. I generally name the drawing (and the surface it contains) based on the method used to derive the surface e.g. Raster 1m contours, raster 50m grid, EGL Topo Survey etc so I can see instantly which one is which...:smileyhappy:
neilyj
(No connection with Autodesk other than using the products in the real world)


IDSP Premium 2015 (mainly Civil 3D 2015 UKIE & Infraworks with some limited 3ds Max Design)
Win 7 Pro x64, 240Gb SSD, 1Tb HDD
32Gb Ram Intel Xeon CPU E5-2650 v2 @ 2.6GHz (32 CPUs), ~2.6GHz
NVIDIA Quadro K4000, Dual 27" Monitor, Dell T5610

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