So I have a topographic map on Civil 3D, is there a way to generate a 3D model of it? Thanks.
Are you meaning a "true" 3D printed scale model..?
If so, first you should solidify your C3D surface, then export it as .STL file to bring to a specialized service.
It depends on the source of the map data. If it is a USGS topo map then you can download a Digital Elevation Model (DEM) from several free GIS servers and build a model from that. The USGS DEM data is created from the data that was used to make the topo maps. However I find the contours from surfaces built from these DEMs do not match the topo map contours very well in some areas, but at least you have something to work with.
The National Map Seamless data server is an excellent source for DEM's, now served in National Elevation Dataset (NED) format. Do a search for Digital Elevation Models. Also reasearch the forum for how to create a surface from an NED file.
If your map was from a non-published source, such as a private survey, then your only recourse, aside from getting the source data, is to digitize the contours.
Nice call Antonio. A 3D printed model never occured to me. Gotta get with the times.