I notice you're asking about a of Autodesk Inventor Nastran, but the way your query ends ("... — solid piece") is a bit unclear.
Autodesk does not offer the full commercial software for free. Descarga gratuita de Autodesk Inventor Nastran ...
Do not search for "cracked," "torrent," or "free full version" from unofficial sites. These almost always contain malware, ransomware, or keyloggers. They are also illegal and can get your computer compromised or your Autodesk account banned. I notice you're asking about a of Autodesk