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Invert Contours (Positive Elv to - Elv)

7 REPLIES 7
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Message 1 of 8
sdrobs
1521 Views, 7 Replies

Invert Contours (Positive Elv to - Elv)

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

7 REPLIES 7
Message 2 of 8
Alfred.NESWADBA
in reply to: sdrobs

Hi,

 

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

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at ... blog.hollaus.at ... CDay 2024
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(not an Autodesk consultant)
Message 3 of 8
thepworth
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 

Message 4 of 8
sdrobs
in reply to: sdrobs

Thank you, i will give that a try.

Message 5 of 8
BrianHailey
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 J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 6 of 8
sdrobs
in reply to: sdrobs

Thank you so much, that worked.

 

Shawn

Message 7 of 8
thepworth
in reply to: BrianHailey

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

Message 8 of 8
BrianHailey
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 J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

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