Manually download the asset archive and unpack it into your %USERPROFILE%\Documents\ folder, then restart V-Ray to restore offline capability.
Once you have the assets on a portable drive, you can install them on a machine without internet access using the Chaos universal installer: vray 6 material library download offline
Use the V-Ray installer and choose the "Advanced" option to ensure the material library files are installed locally. Manually download the asset archive and unpack it
This approach ensures that V-Ray 6’s material library remains a asset database — critical for professional rendering without internet dependency. vray 6 material library download offline
While the Cosmos Browser is cloud-based, it allows for local storage once materials are downloaded. V-Ray Material Library Browser - Chaos Docs