Yes we can. I do it with all terrains now. In your texsrc folder create a 64x64 .bmp named gndbump0 or gndbump1, depending on the texture set your are using. Start off with the 64x64 grayscale .bmp being RGB128,128,128. This solid color will give you no ground bumping at all. If you edit the .bmp with lighter & darker shades of gray, it will change the ground bumping effect. This single .bmp affects all the textures in the terrain i.e. one ground bump pattern per terrain. I assume you can use a larger .bmp, but that is what Skuzzy told me to use my first time I did it. I prefer to remove the ground bumping when using custom textures because it blurs them so badly when seen from the air. This method removed the ground bumping regardless of a player's individual graphic settings.