Change Comparison surface on a Volume surface Civil 3D

[cadjunkee]

I have a volume surface in Civil 3D which has a base surface and a comparison surface. I want to know if there's a way to change the comparison surface? Without having to create a new volume surface.

Reason I ask is because I have a Volume surface based on an existing ground surface and a subgrade surface and once every week or so we get a new subgrade surface from our client and I have to go through the process of creating a new volume surface. I want to know if I can keep the old volume surface and just change the comparison surface to read the new sub-grade.

[sinc]

No, but you can workaround the problem by using a third surface.

As an example, create a third, empty surface - I'll call it "Surface C". Now paste your SG Surface into Surface C, and create your volume by comparing your EG Surface to Surface C. When you get a new SG Surface, delete your existing SG Surface and pull in the new one, then paste your new SG Surface into Surface C.

[cadjunkee]

Hey sinc,

Thanks for the answer, not sure why I didnt think of doing it like that! Still would be nice if you could just change the surfaces with a drop down menu, who knows maybe Civil 3D 2015..?

[sinc]

Maybe...

Another thing that causes people problems is that Spot Elevations cannot be reassigned to a new Surface. You can work around that issue in a similar manner, though, by attaching your labels to a "dummy" surface, and then pasting other Surfaces into the "dummy" surface. (You can also work around the problem by using a different label type, such as a General Note or Cogo Point label, and setup a Reference Text component to the Surface. But that forces you to pick the Surface each time you create a label.)

Kind of clunky, eh? But it works. And yeah, hopefully one of these releases will simplify this stuff so we don't need to use the "dummy" surfaces anymore.