Tacx NEO and NEO 2/2T smart trainers can simulate the feel and rolling resistance certain road surfaces in FulGaz. This includes cobbles, gravel, dirt, sand, wooden bridges and a number of other structures. You can identify FulGaz rides that contain road feel data by the "RRF" symbol on the video thumbnail.
To turn on Real Road Feel, head to FulGaz settings (the "cog" icon in the top right) then scroll down to Trainer Settings. Tick the box next to Real Road Feel.
Enabling RRF also changes the rolling resistance of these surfaces not just for the Tacx NEO, but for all trainers. When turned on, the gravel or dirt road sections will feel tougher and slower than a smooth bitumen road. However, you will only feel the differences in the road terrain with the Tacx NEO.
NOTE: Mains power needs to be connected for Real Road Feel to operate on Tacx NEO trainers.