Using Project Infinity offline - ALIENQuake/ProjectInfinity GitHub Wiki

In order to use Project Infinity offline you need to:

1. Download the latest WeiDU package from https://github.com/WeiDUorg/weidu/releases/latest and extract it
2. Copy WeiDU executable into \Tools\WeiDU\xxx.xx\ (where xxx.xx is the full version number for eg: 240.02)
3. Make sure that none of the mods which you use require a higher WeiDU version than you have locally

After performing those steps, you should be able to use Project Infinity normally.