You may receive an ESRI Shapefile collection from a GIS user for a data source in generating a surface. This is typically a ShapeFile Type 1 (Point) or Type 2 (Polyline) which contains the XY values in the .SHP file, along with the elevations in a field of the associated .DBF file.
The ESRI Shapefile is a common exchange format with GIS systems and users often receive .SHP files representing contours. However, most of the time the elevation data is not stored on the shapefile geometry, instead it’s a column in the associated .DBF file. This typically leads to multiple steps having to import then do processes to read the attached data to elevate them properly, so why not do it all in one step.
The process of importing contours from shapefiles is actually a two step process, since the results from Autodesk’s MAPIMPORT command does not elevate the resulting polylines. This is a step-by-step procedure on how to take a shapefile of contours to elevated polylines in AutoCAD (Map/Civil3D).
ESRI Shapefiles are not just the SHP file. While some importers can import the geometry from just that one file, a lot remains missing. That’s why it’s important to send the package, not just a single SHP file.