I've dowloaded in the database the tutorial How to build a track in 60 minutes by Dave Hagenaars. He says we need 3deditor version 14.7 but the site of the realgpx is dead. Is someone has it at random ? I think it helps me to create dat files cause this is the first tutorial I found. Many thanks !
3DEditor is now GP4Builder, which you can get the latest version here: [www.grandprixgames.org]
It has changed a lot since the old days of 3DEditor but the basics in building a track are the same, so I think you'll still be able to follow the tutorial with the latest software.