Importing Terrain Data from Autocad .dwg file

[tomclerkin]

Hi,
I’m importing terrain data from a .dwg file from a land surveyor.
Unfortunately, they “flattened” the data to 2-D so when I import it, I can see the contour lines but there is no depth when I take a 3-D view.
Any suggestions on how to convert it back to 3-D?

Any suggestions about the best file format to receive terrain data?
Good training video about importing terrain video?
Thanks,
Tom
PS. They surveyor did that because he added other useful stuff to the drawing which could be helpful. If I can convert it back, it should reduce extra work need to model the stuff he added.