Combining/Subtracting Surfaces

[mrsusan]

Hi,

I was wondering if anyone could help. Using base contour data (polylines), A designer converted them to a surface and created a grading for a proposed storage area (Please see attached screenshot). The storage area contains 4 pad style infills, with a cut/fill grading. We'd like to somehow combine these surfaces so that the background contour surface incorporates the new grading (i.e. the existing contours in the infill area to be flat). Does anyone know a method in which to do this?

If i were to switch to realistic view, I can see the fill sections but obviously the cut areas still have existing terrain over it. Any help would be much appreciated. We are using Civil 3D 2010.

[Glenn Pope]

There are a couple ways of doing this depending on how you want the final product to look like.

If you want the contours to look the SAME between the existing and proposed:
Create a new surface. This surface will be a composite surface. Past in the existing ground, then past in the proposed surface. This new surface will update when you make changes to either of the original surfaces.

If you want the contours to look DIFFERENT between the existing and proposed:
Use a mask to mask out the area of your proposed surface.

[mrsusan]

Thanks for the reply - it didn't like the mask but creating a composite surface has done the trick, I tip my hat to you sir!