I am running Prepar 3D v4 and have loaded REX Texture Direct Enhanced Edition and have found after enabling the wet runway effect and bump map grass effect they do not for some reason function in game. Do I need to tweak the games registry to enable these graphical effects. ❓
Your best bet is to post this question here.
https://www.realenvironmentxtreme.com/forums/
They know more about it than we would.