AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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sdrobs
Posts: 3
Registered: ‎04-10-2012
Message 1 of 8 (309 Views)
Accepted Solution

Invert Contours (Positive Elv to - Elv)

309 Views, 7 Replies
04-10-2012 11:48 AM

I have a contour map that i need to flip all the postive contours to negitive. So the Z cordinate for example is Elv 40 now i need to invert it to -40. I want to do this to the whole large contour map. ????

 

Shawn

Create a surface from the contours (do all the minimizing flat area options, you can read why HERE) if it's not already a surface. Create a flat surface at elevation 0 that's totally encompasses your surface. Create a volume surface that compares your surface as the base surface and the 0 surface as the comparison surface. Have the volume surface display contours. Extract the contours from the surface (if you don't want to have the surface).

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Alfred.NESWADBA
Posts: 9,595
Registered: ‎06-29-2007
Message 2 of 8 (307 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 11:50 AM in reply to: sdrobs

Hi,

 

set the UCS to look from the right side (or from front) and then mirror your contours.

 

- alfred -

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Alfred NESWADBA
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Distinguished Mentor
thepworth
Posts: 525
Registered: ‎03-02-2011
Message 3 of 8 (293 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 12:59 PM in reply to: sdrobs

is it contour data or contours representing a TIN/DEM?

 

If its contours as CAD objects, you could use the Map3D side of C3D to perform a drawing query to multiply all contours by a (-1) value and then recreate the surface.  

 

I'm not a fan of surfaces from contours w/o the breaklines.  The software has gotten better, but there's still a loss.

 

The miserable brute-force way would be to export to xml and then replace the elevations with a "-" character.  dunno even where to approach that 


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Member
sdrobs
Posts: 3
Registered: ‎04-10-2012
Message 4 of 8 (274 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 03:30 PM in reply to: sdrobs

Thank you, i will give that a try.

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BrianHailey
Posts: 2,868
Registered: ‎04-27-2005
Message 5 of 8 (265 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 04:11 PM in reply to: sdrobs

Create a surface from the contours (do all the minimizing flat area options, you can read why HERE) if it's not already a surface. Create a flat surface at elevation 0 that's totally encompasses your surface. Create a volume surface that compares your surface as the base surface and the 0 surface as the comparison surface. Have the volume surface display contours. Extract the contours from the surface (if you don't want to have the surface).

Brian Hailey
CAD-1.com
My Blog
Member
sdrobs
Posts: 3
Registered: ‎04-10-2012
Message 6 of 8 (264 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 04:14 PM in reply to: sdrobs

Thank you so much, that worked.

 

Shawn

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thepworth
Posts: 525
Registered: ‎03-02-2011
Message 7 of 8 (253 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-10-2012 08:49 PM in reply to: BrianHailey

Guess I was having a "blonde moment" when I didn't think of that one ealier - nice!


C3D 2011
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12GB Ram / Win7 Professional 64bit SP1
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BrianHailey
Posts: 2,868
Registered: ‎04-27-2005
Message 8 of 8 (241 Views)

Re: Invert Contours (Positive Elv to - Elv)

04-11-2012 07:27 AM in reply to: thepworth

It's a technique I used to use in LDT to help delineate watershed boundaries, create an inverted surface and use the water drop tool on it.

Brian Hailey
CAD-1.com
My Blog
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