AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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CivilDavid
Posts: 64
Registered: ‎04-08-2010
Message 1 of 13 (1,190 Views)
Accepted Solution

Need to create a shape with a hole in it

1190 Views, 12 Replies
09-21-2011 01:09 PM

I have closed polyline within another closed polyline.  I need to create a shape and I need a hole in it.  See attached pdf for example.  Ignore the dashed and solid grey lines, not sure what those are.

 

When I select the two polylines, and select treat closed polylines **** polygons, then I export as shapes, I just get two solid shapes, one on top of the other.  Any help would be greatly appreciated.  Thanks in advance.

 

Hi,

 

as long as that are only few POLYLINEs you can start the command MPOLYGON. With this command and the option to choose elements you can select the POLYLINEs and will get a new object containing one outline and as many islands as you selected. This object can then be exported to SHPs.

If you have many objects, you would have to build a map-topology and then export the topology with MAPEXPORT.

 

HTH, - alfred -

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Jeff_M
Posts: 4,433
Registered: ‎07-22-2003
Message 2 of 13 (1,177 Views)

Re: Need to create a shape with a hole in it

09-21-2011 01:24 PM in reply to: CivilDavid

Convert the plines to regions, then Subtract the smaller one from the larger one.

Command: REGION

Select objects: 1 found

Select objects: 1 found, 2 total

Select objects:
2 loops extracted.


2 Regions created.

Command:
Command: _subtract Select solids, surfaces, and regions to subtract from ..

Select objects: 1 found

Select objects:  Select solids, surfaces, and regions to subtract ..
Select objects: 1 found

Select objects:

Command:

 

Jeff_M, also a frequent Swamper
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Alfred.NESWADBA
Posts: 9,216
Registered: ‎06-29-2007
Message 3 of 13 (1,174 Views)

Betreff: Need to create a shape with a hole in it

09-21-2011 01:25 PM in reply to: CivilDavid

Hi,

 

as long as that are only few POLYLINEs you can start the command MPOLYGON. With this command and the option to choose elements you can select the POLYLINEs and will get a new object containing one outline and as many islands as you selected. This object can then be exported to SHPs.

If you have many objects, you would have to build a map-topology and then export the topology with MAPEXPORT.

 

HTH, - alfred -

-------------------------------------------------------------------------
Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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Valued Contributor
CivilDavid
Posts: 64
Registered: ‎04-08-2010
Message 4 of 13 (1,168 Views)

Re: Need to create a shape with a hole in it

09-21-2011 01:30 PM in reply to: Jeff_M

then how do I export that region as a shape?

Valued Contributor
CivilDavid
Posts: 64
Registered: ‎04-08-2010
Message 5 of 13 (1,163 Views)

Betreff: Need to create a shape with a hole in it

09-21-2011 01:33 PM in reply to: Alfred.NESWADBA

thanks, this worked great.  I've never used the mpolygon command, I always export shapes through MAP, but now I can create the mpolygons the way I like, then export as polygons.  Thanks!

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antoniovinci
Posts: 1,702
Registered: ‎06-03-2011
Message 6 of 13 (1,134 Views)

Re: Need to create a shape with a hole in it

09-22-2011 12:20 AM in reply to: CivilDavid

> then how do I export that region as a shape?

 

You can't.

 


 

About creating "holed" shapes with MPOLYGON, that's good if you start from scratch.

But if you wanna hole an existing shape having Object_Data (GIS attributes), MPOLYGON will destroy them.

In this case, the solution will be the second one from Alfred: _MAPEXPORT of the topology.

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neilyj
Posts: 3,860
Registered: ‎08-01-2008
Message 7 of 13 (1,126 Views)

Betreff: Need to create a shape with a hole in it

09-22-2011 02:20 AM in reply to: Alfred.NESWADBA

alfred.neswadba wrote:

Hi,

 

as long as that are only few POLYLINEs you can start the command MPOLYGON. With this command and the option to choose elements you can select the POLYLINEs and will get a new object containing one outline and as many islands as you selected. This object can then be exported to SHPs.

If you have many objects, you would have to build a map-topology and then export the topology with MAPEXPORT.

 

HTH, - alfred -




How do I go about building a map topololgy??
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
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Alfred.NESWADBA
Posts: 9,216
Registered: ‎06-29-2007
Message 8 of 13 (1,123 Views)

Betreff: Need to create a shape with a hole in it

09-22-2011 02:40 AM in reply to: neilyj

Hi,

 

>> How do I go about building a map topololgy??

In one word? _MAPTOPOCREATE,

In one page? look >>>here<<<

 

BUT don't start the command and think "that's it"!

Try to get training(s) or at least do research around GIS-Topologies and Map3D-Topologies (e.g. >>>here<<<), becaue all data-preparation (MAPCLEAN), the work with object-data, with connected database-tables/views/queries ..and..and..and makes GIS what GIS is and has to be learned.

 

Have a nice day in Google :smileywink: , - alfred -

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Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
-------------------------------------------------------------------------
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neilyj
Posts: 3,860
Registered: ‎08-01-2008
Message 9 of 13 (1,117 Views)

Betreff: Need to create a shape with a hole in it

09-22-2011 02:48 AM in reply to: Alfred.NESWADBA

Alfred - thanks for the info and links.

 

I don't use the GIS functionality day in day out but am sure it could speed up certain tasks for me - I just need to find time to learn about it...!!!!!

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
*Expert Elite*
antoniovinci
Posts: 1,702
Registered: ‎06-03-2011
Message 10 of 13 (1,112 Views)

Betreff: Need to create a shape with a hole in it

09-22-2011 03:58 AM in reply to: neilyj

Neilyj,

I really can't imagine my work in Map/Civil environment without topologies: with them, you make buffers, overlays, create closed polylines, and so on.


Topology is the foundation of every serious GIS job, because it guarantees you only clean and consistent data.


Unfortunately, as said by herr Alfred, to achieve the condition to get a correct topology, you must previously struggle with the _MAPCLEAN command: that's very boring and frustrating, expecially if you have to manage DWGs from other people...

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