Copying Surfaces in Civil 3D

Essential Surfaces – EG and FG 
Surfaces are essential to just about anything done in Autodesk Civil 3D. Often existing surfaces are created and referenced into design drawings, for grading, corridor creation, etc. Existing surfaces are usually named EG (existing ground) or OG (original ground). 
 

For the final design drawings, existing surfaces are represented with contours in half-tone so that they can be plotted out as grey lines. Final design surfaces will have bolder contours. The colors of these final or finished ground (FG) contours should be set to print out with proper pen widths in black. 
   

A variety of other design surfaces derived from corridors or grading objects are also created, and these are usually pasted into one overall final surface. 

Final Surface 
The final or finished surface is usually named FG (final or finished ground). One workflow is to make a copy of the EG, directly on top of it, and rename the copy to FG (and give it the appropriate styles). 
 

Then by pasting in the appropriate design surfaces into the FG, one derives the final ground!  
 

The Old AutoCAD COPY Command 
When I was being introduced to Civil 3D, I searched everywhere (right-click menus, ribbons, etc.) for a special way to make a copy of a surface. It turns out, we simply use the AutoCAD COPY command!  
All you need to do is invoke the COPY command, select the surface, and press <Enter> three times and the job is done.   

Looking at the prompts of the COPY command, first select the surface to be copied. Then, press: 

1. <Enter> to finish the selection set. 
2. <Enter> to say you want to provide values for the displacement (how much the copied object will move), rather than giving a basepoint.
3. <Enter> to accept the amount of displacement of 0,0,0 – which means it will be copied right on top of itself. 
   If one wants to create a grubbing surface, the displacement values will be 0,0,-0.2 (for metric), which will make a copy of the surface 200mm below the original surface. A grubbing surface may be required for topsoil or other finishing membranes. 
    
   Conclusion 
   As the “specialty” versions of AutoCAD become more sophisticated and complicated, it is somehow charming that the regular AutoCAD commands still have a place in our workflows. The old adage of “reading the command line and prompts” still holds true. 

About the Author

Learning Content Developer<br><br>Jeff specializes in infrastructure tools such as Civil 3D and Infraworks, delivering training classes and contributing to the learning guides for these Autodesk software applications. Jeff has worked for several Autodesk resellers and has had roles of both CAD and BIM Manager with Civil and Architectural firms.

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