I generally use both Grome and L3DT to create terrains which requires the ability to import the terrain into both packages from the other. When attempting to export terrain from Grome and then importing it into L3DT using the .raw format I ran into a problem where the imported terrain had zero height strips at tile width intervals running horizontally across the terrain. I suppose that is great if you want regularly spaced moats that run across the entire continent...
The solution involves recompiling the General Export plugin to use a heightmap tile of "size x size" instead of "size+1 x size+1". The details are posted at
http://www.quadsoftware.com/forum/viewtopic.php?t=365