How to offset contour line to a specific elevation?

[martin.hong]

Hey all, new to Civil 3-D so still learning, but basically I have a wetland design and I'm trying to draw in a contour line that would be 0.95 meters below the existing surface. Since the EG changes along the wetland, I don't know a specific elevation, only that it's 0.95m lower. What's the best way to extract this line in Civil-3D? I attached a snippet for reference.

Thanks!

[Udo_Huebner · Accepted solution]

Create an Offset Surface to the EG
using 

1. CreateSurface EG-095 (Command "CreateSurface ")

2. PasteSurface EG (Command "EditSurfacePaste")

3. Lower Surface EG-095 for -0.95 (Command "RaiseLowerSurface")

4. finally create an intersection between EG-095 and the proposed Ground (Wetland Surface) using

(Command "MinimumDistBetweenSurfaces")

[MMcCall402 · Accepted solution]

Another option:

Create a volume tin surface using the EG surface and your design surface.  On that volume surface define a User contour at elevation -0.95.  You can extract that contour if needed.

[jroot · Accepted solution]

Create a polyline at your edge of wetlands. Turn the polyline into a Featureline and get it's elevations from the EG surface. Lower the elev of the Featureline 0.95.