multiple surfaces

hello. can someone help me understand how multiple surfaces work? I have a topo map and i made it as the surface for existing ground. then after that, what will i use as another surface for any proposed element( for example, i have a dam layout)? Will i use the the dam layout and make at as another surface? thank you.

Not sure if this is going to answer your question but here goes... Once you have your existing surface you can then build a proposed surface and generate a cut/fill report. This is just one of the million of things you can do with multiple surfaces. If you can give a little bit more specific question I'm sure others or possibly I could help out.

Another example you have existing then make a design surface say via a complex grading, you then resample a profile so as to reflect say cross sections of a certain area of existing and design. This would be typical of a car park that is made up of multiple profiles joining together.

I built a extreme surface model and it had around 15 iterations of surface steps. The existing was not actually existing but a cross section sinusoidal wave across 50Ha sloped to atch 4 corners fo a project in China with lakes, bridges, pools, roads cutting and going over this theoretical surface.

dear all !!!

how we can get elevation an any vertex in X-section view. please help me

Note: variable offset and variable elevation

Have a look at the tutorials that are part of CIV3D start with HELP and Profiles.