The right "converter" for you depends entirely on what you're trying to accomplish:
This is a classic 3D format, primarily used by Autodesk 3ds Max. It stores mesh data, material attributes, and camera data. While older, it is highly compatible across many 3D platforms. 7z to 3ds converter
Example batch command (Linux/macOS) using Blender headless (conceptual): The right "converter" for you depends entirely on
A .7z file is an archive; a .3ds file is a 3D model format (3D Studio). Converting requires extracting the archive, locating the 3D model source inside, and—if needed—converting that source to .3ds using a 3D model converter or 3D software. It is not a 3D file format itself
A compressed archive file format that supports high compression ratios, encryption, and large file sizes. It is not a 3D file format itself.
Do not upload your .7z files to online conversion websites. These sites are designed for small document formats (like PDF to Word). Uploading a 2GB game archive will take hours, likely fail due to file size limits, and could expose your system to malicious ad pop-ups.
5. Security Warning: Beware of Online "7z to 3ds" Web Converters