Autodesk does not offer a "free public download" for Civil 3D 2013. However, if you have a valid serial number from a legacy purchase, you can retrieve the installer via Autodesk’s Virtual Agent or your subscription center.
If you are attempting to run AutoCAD Civil 3D 2013 today, note these technical constraints: Autocad Civil 3d 2013 64 Bit- Free Download
If you need the software for professional work, you can download a free 30-day trial from the official Autodesk website. Autodesk does not offer a "free public download"
: Cracked versions often lack critical service packs, leading to frequent software crashes. leading to frequent software crashes.