Why are DWG Plant or Civil 3D models missing pipes, elevation grids, textures?

Why are DWG Plant or Civil 3D models missing pipes, elevation grids, textures?

DWG import is currently restricted to basic, classic AutoCAD types of DWG content. Extensions such as models from Civil3D containing textures, elevation grids or models from plant or pipe design using object extenders “OE” are not supported, these elements may be missing from the PDF.